Coffee

SUMMARY

This lecture covers the basic fundamental principles of the coffee plant and its requirements. It is important to understand this information before moving on to the next lectures which are based on describing production and management systems. It helps you to understand the crop in the context of the climate it is grown in, choices that one can make to ensure regular cropping under a range of pruned and free growth systems of production.

The production system chosen must integrate the climate, plant, soil and management to the best advantage for sustainable profit, production and care of the environment, taking into account the likely risks which may occur.

Coffee requires a high level of management. The following lectures provide a basic guide for coffee production and management. More specific information can be obtained from local literature and extension officers.

Dr Michael St.J. Clowes and Peter Chard                    April 2013

1. INTRODUCTION

ORIGIN AND HABITAT

Coffee grows naturally as an understory tree in tropical forests in Africa. Coffee belongs to the Rubiceae family and Coffea is the most important genera and comprises three cultivated species: Coffea arabica L (Arabica), Coffea canephora (Robusta) and Coffea liberica (Liberica).

There are many different types and varieties of coffee. Hybrids occur naturally and are also  produced commercially, sometimes being crossed with wild species to impart pest or disease resistance.

Taking the tree out of the forest and planting it in plantations has increased growth and fruiting potential, but also exposes it to greater pest and disease pressure.

Coffee is a high management crop when grown out of its natural environment. Mulching has great value in any system of production.

COMMERCIAL USE AND VALUE

The fruit is harvested from the trees that are allowed to grow to between 2 – 5 m tall. Tree height and form is usually controlled with pruning and the fruit is either sundried whole or pulped (i.e.  outer fleshy skin removed), fermented and then sundried before being hulled. Hulling removes the tough whitish parchment skin and the thin membranous silver skin which is stuck to the bean.

The sun dried unfermented whole fruits are sold as ‘mbuni’ coffee while the pulped and fermented coffee is sold in parchment form. Both coffees are hulled to produce the ‘green bean’ that can be blended after roasting. Coffee is traded in 60 kg bags of green coffee and the price is quoted in US$ per lb FOB (Free on Board). The green bean is roasted, ground and is then ready for use.

Coffee is the most traded agricultural commodity in Africa. In 2009/10 a total of 93.4 million bags (each weighing 60 kg) of green coffee was traded worldwide (equivalent to 5.6 million tonnes). The value was US$ 15.4 billion at an average price of 125 US cents per lb FOB, (equivalent to 57 US cents per kg). Coffee is a beverage and is also used to flavour foodstuff.

PRODUCTION AND CONSUMPTION

Production is cyclical and extremely influenced by climatic factors such as drought and frost while pests and disease also impact on production. Demand tends to increase by about 1.5 ‐ 2% per  annum but supply is erratic. Shortage of supply results in high prices over a 2 – 3 year period every 10 to 20 years. High prices impact positively on profit and growth of the industry, which ultimately drives production up and prices down. Brazil is the world’s largest producer and has the most influence on the market.

In 2013 the five main producers in the world were Brazil, 55.9 million bags; Vietnam, 22.4 million; Indonesia, 9.7 million; Colombia, 7.5 million and Ethiopia, 6.5 million bags.

The top five producers in Africa were Ethiopia, 6.5 million bags; Uganda, 3.45 million; Cote    d’Ivoire,

THE MARKET

Coffee price is determined by the market which is supplied with four types of coffee. Price is based on type of coffee, process method and quality. The following list is from the highest to the lowest quality:

1. Colombia milds (12%)    ‐ Premium washed e.g. Kenya and Tanzania etc.
   1. Other milds (23%)            ‐ Most other countries with washed Arabica.
   1. Brazilian naturals (31%) ‐ Unwashed Arabica
   1. Robusta (34%)                  ‐ All Robusta  e.g. Cote d’Ivoire

The ICO (International Coffee Organisation) Indicator Price is weighted by the percentages shown in brackets above.

SPECIES OF COFFEE IN COMMERCIAL PRODUCTION

The two main species and a minor species of coffee which are grown commercially are:

• Coffea arabica L., known as Arabica which has the best quality and a high acidity. It is best suited to upland areas within the tropics and fetches the highest price. Arabica can be used in small quantities to make up commercial blends. It is also grown in lowland areas.

• Coffea canephora, known as Robusta is suited to the lowland, humid, tropical areas and is a very hardy type of coffee. It does not like the cold weather, but is resistant to many pests  and diseases. Robusta is used as a bulk in blending, often with Arabica, and has good body and lower acidity.

• The above species are the most common in general blends which are made up to provide  the required balance of acidity, body and flavour. There is a growing niche market for speciality coffees which can comprise specific processing variety or estate which is following on the success achieved within the wine industry.

• Arabusta hybrids (Arabica Robusta crosses), developed in Brazil and Cote d’Ivoire are likely  to replace Robusta in the longer term on account of improved overall potential.

• Coffea liberica, is a minor but complex group also suited to the humid, tropical lowlands. It is less important than the other types but is found in the forests of Central and West Africa.

CLIMATIC REQUIREMENTS

Coffee is rain fed when gown in the highland frost‐free regions. It must receive over 1 400 mm well distributed rainfall annually. Shade and/or windbreaks can be used to advantage in some situations however the trees must be well managed. Only certain varieties are suitable.

Irrigation is required in areas with lower rainfall or short rainy seasons. The rainfall has to meet the plant and crop needs as this prevents biennial bearing, overbearing, and, in more extreme cases, plant dieback.

Cooler climates at higher altitudes favour high quality coffee but lower production. The hotter climates at lower altitudes favour production. These areas produce coffee with a lower acidity and a higher proportion of ragged beans (poorly developed). The best balance is the intermediate altitude but both extremes have a place in the market; one for quality and the other for quantity.

At low, hotter altitudes, the coffee trees require shade to improve bean development. The cova system, developed in Brazil, involves planting 2 or 3 trees per planting station, which helps the tree to shade itself and increases yields in the early years.

In a hedgerow, where 2 plants are planted in a cova, they should be planted side by side in a line along the row.

In separate individual covas, 3 plants are planted in a triangular design close together. Each cova is separated from the next to allow for light penetration when the trees are mature.

The taller, more erect varieties are favoured for the cooler conditions at higher altitudes and the dwarf or semi‐dwarf varieties for the hotter, faster‐growing areas.

Frost kills young plants and growth ceases at temperatures below 11 ‐ 13oC. Above 33oC, conditions are too hot and increase the likelihood of ragged beans. Long periods of high temperatures can  cause sun scorch of the leaves and berries, and predisposes the plant to disease.

Pest and disease incidence tends to increase in areas with warmer winters.

SOIL REQUIREMENTS

Coffee can be gown on a wide range of free‐draining soils provided they are deep enough, preferably at least 1 ‐ 2 m. Details of the fertiliser needs can be found in Lecture 3. The following is a brief summary of pre‐planting needs to help assess the soil suitability:

• The soil must be within the correct pH range to facilitate nutrient uptake and to meet the requirements of the tree and crop. The optimum pH is about 5 ‐ 6 on the calcium chloride scale. Lime should be applied to the soil if the pH is below 5. Note pH in water is 0.5 ‐ 0.7 higher than in calcium chloride;

• Phosphate should be applied to the soil if it has less than 30 ppm available P2O5;

Nitrogen and potassium are the main nutrients required by coffee. Sulphur, magnesium, boron and zinc are also critical micro elements; and

• Sandy soils require additional irrigation and nutrition, but are easier to manage.

Regular soil and leaf analyses on cropping trees assists in determining the amount of fertiliser necessary.

Coffee is often grown on hillsides where conservation measures such as mulching, contours and terracing are necessary.

Figure 1: Young coffee, second year in the land, showing conservation and contours.

Source: media‐2.web.britannica

GROWTH

Coffee is grown from seed in a nursery under shade for 8 ‐ 12 months and is hardened off before being planted out into the field. See Lecture 2 for details on nursery  practices.

Seed can be pre‐germinated before planting.  The hypocotyl pushes the seed above ground (soldier stage). The seed opens to unfold and produces two matching cotyledon leaves (cotyledon stage). Growth of the seedling continues to produce a well‐developed and fibrous tap root system and a central mainstem. A straight strong tap root is essential.

The mainstem produces primaries in a very orderly arrangement. A pair of primaries forms opposite each other with the next pair above at 90o.

Buds below the primary can produce suckers (e.g. after ratooning). Suckers develop primary, secondary and tertiary branches in the same manner as the original mainstem.

A branch comprises nodes, leaf axils, leaves and buds. Growth in the form of shoots or fruits arises from the buds in the leaf axil on the branch. Buds can remain dormant or develop into clusters of fruit or new vegetative shoots.

Secondary branches grow on primaries and tertiary branches grow on secondary branches.

In a single season a branch when first cropping well, can produce 50 – 75 cm of growth which has a maximum of 18 ‐ 20 nodes when young. Mature trees produce less growth and fewer nodes (20 cm growth and 6 ‐ 8 nodes).

Young trees produce their crop on primary branches which is the easiest to harvest. Older trees produce the crop on secondary and tertiary branches as well which makes the tree denser and more difficult to harvest and spray.

Primaries continue to develop until the tree reaches its final height. The primary grows as a vegetative branch in the first year, fruits in the second becoming structural after this as the level of shade from above increases.

Over 3 seasons primaries can grow to over a metre in length. If un‐pruned they ultimately droop and die from self‐shading from above.

The programme of replanting and rejuvenation should ensure sustainable yields with the ability to extend the crop cycle taking advantage of any price hike. It is important not to be too greedy and not keep the trees too long before replanting or ratooning.

TREE POTENTIAL

Early planting and the plant population (the number of trees per hectare) determine the crop potential in the initial cropping years.

As the tree matures and becomes more vegetative (bushy), light penetration has the greatest effect on determining crop potential and reproductive efficiency (fruit per node). An open canopy is required for effective spraying and effective harvesting.

Vegetative extension growth is determined by temperature and is almost continuous over the rainy seasons at the equator. In the tropics, with a single rainy season growth starts when temperatures warm up after winter (August) and ceases as temperatures drop in April and May.

The leaves must be kept on the bush to ensure extension  growth continues actively until winter when low temperatures slow down growth, producing shorter internodes and smaller leaves. If leaves are lost prematurely to pests (leaf miners or leaf eaters), or disease (leaf rust) then dieback can occur on  cropping trees. Poor rainfall years on rain fed crops can trigger biennial bearing.

Biennial bearing can be reduced by allowing trees to grow to 3 metres before cutting them back to 2 metres.

FLOWERING

Flowering is triggered by the onset of rain or irrigation. Blossoming occurs 10 days after rain or irrigation. The flower buds are initiated earlier when growth slows (winter) and with shorter days. This is when buds can also develop into shoots which can make the tree too vegetative.

FRUIT

Fruit is mainly produced on the previous year’s growth and new extension growth is essential to meet the demands of the fruit. Primaries are more productive (carry more fruit per node) than secondaries which in turn are more productive than tertiaries.

A number of flowerings triggered by rain/irrigation can occur per season. Fruit develops in four stages/phases (weeks from blossoming):

1. Pinhead stage              0 ‐ 6      weeks, no visible growth.
   1. Expansion phase         7 ‐ 17   weeks, fruits are ‘glassy’ *
   1. Filling phase                18 ‐ 36  weeks, fruits become hard and grey*
   1. Fruit ripening phase 37 ‐ 45  weeks, green to yellow to red**

*Appearance when cut through with a knife

** Some varieties are yellow when mature e.g. Yellow Catuai

Under cooler conditions coffee can remain red and ripe for a number of weeks on the tree. Under very hot conditions fruit can easily become over‐ripe, resulting in the outer flesh turning black on the tree.

The ripening period varies with the age of the tree. The earlier crop is harvested from younger trees and the converse is true for older ones. This is one of the advantages of having trees of different ages. Pruning also has an impact on crop development.

HARVESTING

Harvesting normally occurs over 3 ‐ 6 months. Single crops are produced with a monopodal (single) rainy season (e.g. Southern Tanzania and Southwards). Two crops and two main growth flushes are produced in areas with two rainy seasons (e.g. Kenya).

DIEBACK

Dieback can cause poor fruit development and premature blackening of fruits. It also results in the vegetative and reproductive components getting out of balance.

Figure 2: A coffee tree with two mainstems and fruit on primary branches

Source: whyfiles

Figure 3: Showing progressive development of the branching framework

• PRUNING

Coffee is a perennial evergreen tree and is managed by pruning to allow for harvesting and management of pests and diseases. The system of pruning determines the time to replant or ratoon. Ratooning is the cutting back of the plant to a stump about 0.3 m above ground which allows the selection of 2 ‐ 4 new suckers to grow out to replace the original tree.

Pruning saws are used for mainstems, secateurs for the branching framework and finger and thumb to remove suckers or thin out new shoots. Good hygiene is vital to prevent the spread of disease.

Tools are disinfected (e.g. using a domestic cleaner such as Jik) and sick trees removed separately  and burnt.

Pruning encourages further growth, therefore, there is a need to de‐sucker and thin out newly initiated shoots which often has to be repeated in the growing season.

The three systems of tree management are described below and illustrated by the diagrammes that follow:

• The conventional single stem pruning system results in a continuous and cyclical replacement of lateral branches from primary branches;
• In contrast the multiple stem pruning system depends on the cyclical replacement of the 2  to 3 vertical stems which are the main stem and suckers; and
• Single and multiple stem pruning are recommended for the slower growing cooler areas.
• In hotter areas with more rapid growth, a free growth system is used in combination with ratooning once or replanting. Capping (cutting back the tree from 3 m to 2 m) can be used to extend the crop cycle. De‐suckering is recommended and minimum pruning used as it encourages excessive growth.

Pruning should be done as soon as the crop has been harvested and before the start of the next  rainy season. Any crop left on the tree is stripped off and sundried or pulped before pruning.

Pruning modifies the growth habit to get a balance between vegetative and reproductive growth. It opens up the tree to allow for effective spraying for pest and disease control and harvesting. Pruning improves reproductive efficiency in the older parts of the tree.

Pruning wounds to the mainstem or well developed primaries should be treated with a fungicide reducing the chance of infection.

Primaries must never be cut back to their base unless no further growth is required. If growth is required at least two nodes should be left. This provides a source of buds to form new vegetative shoots. This is termed Parrot perching.

Pruning is best done under dry conditions.

SUMMARY

This lecture helps to explain the operations and resources required for starting a coffee nursery. The nursery and planting operations are keys to achieving a good start. The production and use of mulch should be an integral part of the system. Timeliness, standard of work and attention to detail are essential elements for success and these principles apply to all coffee growing operations.

Dr Michael St.J. Clowes and Peter Chard                    April 2013

1. THE COFFEE NURSERY

PROPAGATION

The most common way of propagating coffee is by seed.

Kenya developed Ruiru 11 which is a hybrid variety bred for resistance to Coffee Leaf Rust (CLR) and Coffee Berry Disease (CBD).

Vegetative Propagation (VP) has been done successfully using tissue culture for both Robusta and Arabica coffee has used leaf meristems and growth media to produce plantlets.

Grafting rootstock seedling to scion from seedling has been done in Malawi, but not for commercial use.

SITE

Nurseries and seedbeds should be prepared on good soil in frost free areas with good quality water. Any vegetation below the nursery that might prevent cold air from draining away must be removed.

Ensure there are good firebreaks of at least 5 m wide round the nursery.

The area required can be calculated using the following example based on plant requirement, pot size, pot arrangement and pathways.

This design is for 5 555 pots plus 10% contingency. Pots of 13 cm diameter are placed in blocks holding 500 pots (50 long by 10 wide) with a 0.5 m pathway. This will cover a surface area of 155 m2 per hectare to be planted. This can be used as an initial guide to establishing a nursery.

Overhead shade protects the seedlings from sun, frost and hail. A 50% dapple shade can be provided by thatching grass supported by wire or wattle. Alternatively 70% shade netting can be used.

In areas where frost might occur, the top end of the nursery area must be completely enclosed to prevent the entry of air. The sides should be enclosed to waist height whilst the lowest side completely open to allow cold air to drain out. Ensure netting prevents entry of animals and birds.

TIME OF SOWING

Planting seed direct into the lands is not recommended as survival rates are very low and management requirements very high.

The time to sow is linked to the proposed time of planting out into the field. Planting into the field occurs with the rains under rain fed conditions or before the rains under irrigated conditions.

The interval between sowing the seed in the nursery and planting out into the land is about 8  months for the hotter conditions and over 10 months for cooler climates.

A mature seedling should have at least 6 ‐ 8 pairs of leaves and be 20 – 30 cm tall. This is before seedlings start to branch and the tap root must not be kinked. Roots must be evenly distributed within the pot. Seedlings should not be etiolated (spindly) or pot‐bound (roots dense, bunched and curled in on themselves within the pot).

Plants must be hardened off in the nursery before planting out by gradually reducing the shade over 4 ‐ 6 weeks. Eventually shade should be removed completely for at least a few weeks provided there is no risk of frost.

Planting into the land as early as possible ensures good early yields and reduces the incidence of pests and diseases.

Seedlings have difficulty in growing in cold or very hot conditions.

Planting out in very hot and dry weather in the summer months should be avoided as young plants are sensitive to heat (over 33oC) and dry conditions (difference between wet and dry bulb at 2pm being above 6 to 8oC). Temporary shade will help at plant establishment.

Try to plant out into the field at a time when natural rainfall or irrigation will help the plants to become established.

Seedlings should not be kept over in the nursery for longer than a year as they become spindly and pot‐bound. In special circumstances plants can be cut back to promote new growth and delay planting out.

Below are recommendations for a climate such as in Zimbabwe with a single rainy season (November/December to March/April) and with winter from May to August.

Seed Sown	Planting Out
July / August	January / February	This will allow the plants to become established before the winter.
November / December	August / September	Allows the plants to become established before the heat in October. This is the best time for planting out. Beware of frost.
January / February	November / December	This takes advantage of the early rains.

SEED

Arabica is self‐pollinating so that a farmer’s seed can be used. There are very few mutants (off  types

• such as plants with very spindly stems or purple leaves and fruit). Robusta is out‐crossing and plants are more variable.

Where there are threats from disease (e.g. Coffee Berry Disease and Fusarium), seed is produced in disease free areas and growers are recommended to grow certified disease‐free seed.

It is important to appreciate that imported seed from other countries must meet with phytosanitary requirements.

Coffee seed loses its ability to germinate quite quickly after harvesting and the beans which have been picked most recently should be used for seed.

Freshly picked, fully‐ripe berries should have the skins removed by hand and dried under shade.

As a rough guide for Arabica there are approximately 4000 ‐ 5000 seeds per kg. Allow approximately 3 kg per ha allowing for any contingencies. Robusta is smaller and more variable and allow 7000 ‐ 8000 seeds per kg. Seed can be treated with a suitable fungicide or insecticide, recommended and registered for use in coffee. Labels should be checked for details of use, safety and storage.

Seed can be pre‐germinated or planted directly into seedbeds or standard perforated plastic pots or sleeves (20 cm x 25 cm when flat often referred to as layflat, with 13.5 cm diameter when filled). Large Jumbo pots containing twice the volume of soil are used when more than 1 plant is grown per pot.

Pre‐germination is done in a warm environment using artificial heat or under a plastic tent. Pre‐ germination ensures efficient use of seed and pots and a more even plant growth. It reduces the time in the nursery by about 3 weeks. Seed is placed in a single layer on a suitable medium such as clean hessian bags or sand and lightly covered with hessian or other suitable material (e.g. dry, fibrous grass). It is advisable to pick out the seed as soon as it has germinated, with less than 3 mm protruding from the seed. This makes it easy to sow and ensures that the tap root is not damaged in the process.

It is possible to pre‐germinate to the rooting stage before transplanting. This is provided extra care and supervision is given to ensure the tap root remains straight and undamaged at planting. A hole is carefully made with a 6 inch nail to allow the root to enter the soil without kinking. The surrounding soil then has to be gently pressed inwards towards the root with fingers to ensure the soil is firmed up against the root and there are no air pockets around the root.

It is important to keep a record of which workers planted which beds to encourage a high standard  of work.

SOIL

Pots should be filled with a mixture of virgin (free of eelworm) sandy loam top soil, collected to a depth of 25 cm from the site selected. The soil should be analysed for pH and phosphate in a full chemical analysis.

Topsoil is used as it has the best organic matter and nutrient status.

Add well‐rotted compost and/or well‐rotted manure to the soil (1 part to 3 ‐ 4 parts soil by volume). Sieve compost, soil and manure to remove sticks, stones, etc. Mix together thoroughly the required quantities of soil, compost/manure, lime, phosphate and soil insecticide with a spade. This mixture is used to fill each pot. If beds are used the ingredients are placed on the surface and mixed well in to a depth of 25 cm. It is also possible to add the phosphate and insecticide to the pots after potting and mix them in.

Check that after a good watering there is about a 5 – 10 mm lip which allows for effective catchment of water by the pot.

A funnel of suitable diameter (e.g. 12.5 cm) for the standard pot can be used to facilitate the filling. About 1 m3 soil fills 300 pots.

Pots should be filled with soil and placed in the nursery for 2 ‐ 3 weeks to allow the soil to settle before sowing the seed.

WATERING

The seed and seedlings must be kept watered and never allowed to dry out. Light watering is  possible to start with, but once the seedling is growing the pot must be well watered so that it is wetted through to the bottom of the pot. Check pots at the sides and in the middle of each bed by feeling the base of the pot by hand. It should be soft, not rock hard and not slushy. Water with a  light rose head on a watering can or hose pipe. For larger nurseries a micro‐jet system is recommended. Watering must consist of small droplets applied uniformly over all the pots.

Source: islandsuncoffee

SOWING

Seed should be sown with the flat side down and inserted to a depth of 1 cm with the tip of the  index finger. Use the thumb against the index finger to control the depth of sowing. Depth of sowing needs to be correct and well supervised. It is best to sow, check, then cover and, check again. This is four separate operations.

Sow the required number of seed per standard pot:

• Pre‐germinated seed ‐  1 per pot
  • Directly sown seed    ‐  2 per pot

Plant single seeds in the middle and when more than 1 seed is sown per pot place them 2.5 cm apart and thin to 1 plant once the first pair of true leaves appear.

Larger Jumbo pots are used for covas which are planted with 3 seeds and usually thinned to 2 per pot.

Alternatively, planting can be directly into beds with a distance between rows 15 cm and planted 15 cm apart in the row.

MULCHING

The soil surface of the pot should be covered using coarse  sand (free of eelworm) or chopped dry fibrous grass such as Eragrostis cut into 2 cm lengths. Mulching prevents the soil from capping and retains the moisture in the pot.

The seeds start to germinate 6 ‐ 8 weeks after sowing. Once the shoots appear, carefully remove some of the grass mulch to allow the seedlings to grow unhindered. The seed is pushed up through the mulch by the hypocotyl (stalk).

• PLANTING

Before the plants are removed from the nursery they should be well watered after the hardening off period.

Plants should not be left for long periods in full sunlight. The plants in pots should be loaded  carefully into pallets or directly into trailers or trucks for the journey to the lands. If plants have been produced in beds they must be carefully dug up with as much soil as possible on the roots. The roots must be kept moist, cool and shaded using wetted hessian which is especially important under hot and dry conditions.

LANDS

Lands must be well prepared (ploughed, ripped and weed free) 2 ‐ 3 months before planting.

Young coffee plants should be planted into clean weed‐free ground as they cannot stand competition from weeds. Perennial creeping grasses and water grass should be eradicated before planting is considered.

Holes measuring at least 45 x 45 x 45 cm should be dug in the lands well before planting (approximately 3 months) to loosen up the soil. The hole is then backfilled to allow the soils to settle and compact before planting. When digging the hole the topsoil and subsoil are kept in separate piles on the soil surface. Manure and/or fertiliser is added to the bottom of the hole and mixed in whilst back filling. When backfilling the topsoil from the hole and surrounding surface, topsoil is  used. The subsoil from the hole is then spread over the surface helping to control weeds.

Allow the soil in the hole to settle for 4 ‐ 6 weeks before digging the planting hole. These holes must accommodate the pot. It is preferable for holes to be too deep rather than too shallow. Shallow holes have to be re‐dug just before planting and planting into a shallow hole is likely to damage the fragile tap root.

When planting, cut the bottom off the pot and ensure the tap root is straight and has not become bent at the base. Place pot in the hole which must be a little deeper than the pot, and use a knife to slit open the pot from the base to the top. The surface of the plant soil must be level with the surrounding soil in the field. Remove the plastic from the seedling. It is a good idea to check that the numbers of the used plastic pots collected tally with the nursery off take, to ensure that plants are not planted in the pots. Replace the soil by hand around the plant firmly.

When re‐planting plants from beds, the roots are bare rooted and must be kept moist and shaded. Most important is that the tap root of the young plant is straight and undamaged at planting.

Once the plant is positioned in the hole at the correct depth loose soil is added and pressed down firmly with open fingers.

An insecticide and mulch is usually applied to the soil at planting in a ring (50 cm) around the plant and 20 – 25 cm away from the mainstem.

PLANTING DISTANCES

Plant arrangement can vary depending on the system of management chosen. Four examples are given below:

·         Conventional System

Distance between plants (Planting Stations) 2.4 x 2.4 m with either 1 or 2 plants at each station.

·         Conventional with standard small tractors

Distance between rows is 3 m or more and between plants in the row 2.4 m or more. The wider row spacing allows for vineyard tractors to operate.

·         Hedgerow System

Plants are set out so that when they mature they will form a continuous hedge. Natural coffee trees have a radius of 1 metre so that planting 1.5 m apart in the row will produce a hedge in the third season. The distance between the rows can vary between 2.4 ‐ 3.0 m. This system provides good shelter but the trees need to be skirted once the hedgerow forms in frost‐prone areas to allow cold air to flow down through the plantation.

·         Covas

This is a system of planting 2 ‐ 3 trees at each planting station. Slightly wider spacings can be used. It combines intensive production with ease of management. More  trees  increase yields early on whilst using covas facilitates light penetration later on. It is important to have the 2 plants planted alongside each other along the row so that they tend to be supported by the hedgerow instead of falling into the row to impede tractor movement.

MULCHING

This is the practice of applying a layer of dead organic material to the surface of the soil around the trees in a plantation. Mulching has proved very beneficial, although it increases the costs of coffee growing and is labour intensive.

Mulching has the following benefits:

• Reduces germination and growth of weeds;

• Improves the structure and permeability of the soil by adding humus to the soil;

• Conserves moisture in the soil by reducing evaporation from the soil surface;

• Less irrigation is required;

• Improves water infiltration and reduces erosion;

• Moderates soil temperature by preventing the soil from becoming too dry and hot. This is important with young plants, which can be damaged by excessive heat. The mulch helps to keep the roots cool and the plant supplied with water; and

• Supplies nutrients to the tree, particularly potash. Generally mulching improves both the quality and yield of the coffee crop.

The mulch should be in a ring around young coffee trees, but a clear area (20 – 25 cm) should be left around the stem of the tree. It is best to apply a thick layer of mulch outside the tree’s dripline (canopy circle). In mature coffee plants mulch is placed down alternate rows. It is preferable for mulch to break down before the roots inhabit the mulched zone.

Mulch also has certain disadvantages, which have to be considered.

• Mulch poses a frost risk. Apply mulch at planting (i.e. just before rains) so that it is broken down before the risk of frost in the following winter. Mulch can be used to cover young plants protecting them from frost. A layer of mulch above ground level traps cold air in the winter and if this touches the stem of the tree it, can suffer frost damage. It is common practice in older plantations to mulch alternate rows. One can start with even rows,  followed by the odd rows the following year. This reduces costs and allows for a good layer  of mulch to be applied;

• Mulch locks up nitrogen and the C:N ratio (carbon to nitrogen) is important. The more fibrous the mulch the longer it takes to break down and the longer it locks up the nitrogen. That is the rationale for applying mulch outside the drip line to ensure that the nitrogen applied is not locked up;

• Mulch poses a fire risk so it is important to minimize risk by not having a complete cover. A good example is alternate row mulching in mature coffee. Irrigation tends to reduce this hazard; and

• Mulch increases pest incidence (e.g. Dusty Brown Surface Beetle) and insecticides need to  be used to combat this threat in vulnerable areas. Mulch should never be applied right up to the mainstem.

Veld grass (e.g. Hyparrhenia spp.), maize stalks and other crop residues are used for mulching. Napier Fodder grass is the most suitable material to grow as a source of mulch. The Napier grass must be properly managed (weeded, fertilized and ploughed out after 5 years). The grass should be allowed to dry before stacking. Cutting and stacking take about 9 man days per ha.

One hectare of well grown Napier Fodder will provide enough material for 2 hectares of coffee,  using alternate row mulching. The mulching material should cover the ground to a settled depth of  at least 10 cm.

A practice sometimes carried out is to plant a crop between the rows of young coffee in their first year in the lands. Crops used for this purpose are soya beans, groundnuts, sunflowers and sun hemp. After harvesting the crop residues can be left on the land as mulch.

Depending on the topography of the plantation, shelter belts can be planted to protect the trees from the prevailing wind. Care must be taken to ensure trees do not trap cold air in areas prone to frost. Cold air must be allowed to flow down the hillsides and away from the plantations. Shelter belts add leaf litter as mulch to the plantation but also compete for water and light.

SUMMARY

Weed control is based on an integrated programme involving the use of mulching, hand pulling, hoeing, slashing and herbicides (pre‐emergence, post emergence and contact).

Attempt to keep the rooting zone free of weeds, particularly when there is a shortage of moisture.

The programme must monitor the weed spectrum and ensure control of problem weeds such as creeping and water grasses.

It is important to know how to calibrate a knapsack, to always double check the calculations and check as the work progresses that you are still on track.

Fertilization should be based on leaf and soil analyses.

This lecture provides a good guideline and shows how calculations are made and how the nutritional requirements change with the age of the crop to maturity from 4 years in the land.

Rates for coffee older than 4 years can also take into account the crop potential, as well as leaf and soil analyses results.

Dr Michael St.J. Clowes and Peter Chard                    April 2013

1. WEED CONTROL

INTRODUCTION

Coffee yields can be severely depressed by weeds which compete for water, nutrients or light when the coffee is small.

Weed control is generally achieved by a combination of hand pulling, mulching, mechanical (e.g. hoeing and slashing) and chemical (herbicides) use. It is of the utmost importance to control weeds within the rooting zone. The farmer must plan to control weeds using an integrated programme and take into account the following:

HAND PULLING

Young coffee should be weeded by hand near the base of the plant, as hoeing is likely to damage the plants.

MULCHING

A ring of mulch around the plant is ideal during the first year in the land. However, the following should be taken into consideration:

1. Do not apply the mulch closer than 20 – 25 cm to the main stem so that any insect damage to the stem can be noticed immediately;
   1. Control soil insect pests, e.g. Dusty Surface Beetle by using a suitable insecticide; and
   1. Remove the mulch at the end of summer in areas where there is a risk of frost.

HOEING

Never use a hoe to remove weeds within 20 – 30 cm from the main stem. Weeds in this area should be removed by hand before hoes are allowed into the field.

Hoes increase the risk of:

• Plant damage;
• Erosion; and
• Surface capping or crusting.

SLASHING

This can be done down the interrow during the first year in the land and down the row in mature coffee. Ensure that weed growth is controlled in dry periods when the weeds compete with the crop for limited moisture.

HERBICIDES

Careful attention should be paid to the following:

1. Choice of herbicide (e.g. Gardomil and Dual pre‐emergence for young coffee);
2. Rate to be used (follow label instructions);
3. Application of the herbicide, (e.g. weed‐free and moist for pre‐emergent herbicides);  and
4. Herbicides, when wrongly applied, are likely to:
   1. Provide inadequate weed control; and
   1. Cause damage to the coffee plant e.g. Gramoxone.

The farmer should decide on the type, rate and method of applying the herbicide. Some guidelines on the application of herbicides are given below:

Spray application of herbicides (knapsack or tractor mounted)

Initial Checks:

1. Ensure each spray operator has protective clothing as indicated on the chemical label;
2. Use water to initially check that the sprayer is working properly with no leaks;
3. Check that the nozzle selected is providing a uniform cover to the target area; and
4. Check calibration and re‐calibrate if necessary.

Calibration of a knapsack sprayer (using water):

• Ensure that the correct nozzles are fitted for herbicide application (coarse droplets to reduce drift)

• For Example: D 2.0, D 2,5; Flat Fan Polijet ‐ different colours for different swathe widths:

• Yellow (to 0.5 m), Green (to 1.0 m), Blue (to 1.5 m), Red (to 2.0 m).

• Check nozzle charts for use, pressure, flow rate and swathe width based on height above ground.

• Assume required swathe width 0.75(SW)

• Select nozzle pressure and height above ground;

• Mark off a distance of 100 m (using tape). When walked there and back, total length of test run is 200 m.(L);
  • Fill the sprayer with water and test to ensure that the lance is operating properly.

• Top‐up the sprayer with water. Capacity when full is 20 liter. (C);

• Walk the test run of 200 m whilst spraying, maintaining a steady walking pace and pump at a constant rate (slowly – one stroke per second) to maintain even pressure. Time the speed as a check in the field later (m/sec);

• Check swathe width (SW) of spray, holding nozzle at the correct height above ground whilst walking in a straight line down each side of the row;
  • Measure the quantity of water (Q) required to top‐up the tank using a graduated measure filled to the same mark each time;

Calibration example:

• Mean volume of water used for 4 test runs = 4.5 + 4.3 + 4.4 + 4.4 Total = 17.6 litres/4. Average = 4.4 (Q).

• Calculate Test Area sprayed (AS) = (L X SW) 200 x 0.75 = 150 m2  (AS) /10000 m2 hectare) =

0.015 ha

• Calculate Test Water/ha (WH) (Q/ASX10000) = 4.4/150 x10000 = 293 litres/ha (WH)

• Calculate area Sprayed with FULL KNAPSACK (KA) (m2/ha/WH X C) = 10000/293 x 20 = 682 m2 (KA).

• Calculate number of knapsacks full to spray one hectare (KHa) = (WH/C) 293/20 = 14.65

(KHa)

• Calculate Product (P) per knapsack (K) of 20 litres. Recommendation from chemical label for soil type is to apply 2 litres per hectare sprayed. Quantity Product per Knapsack = (P/KHa) = 2/14.65 = 0.136 kg x 1000 (g/ha) = 136 g/knapsack (P/K);

• Double check spray instruction, label information and confirm that it makes sense. Mix the chemical and water once you are satisfied that the calibration is correct. If you are in doubt check with an herbicide consultant. Weigh out herbicide for each tank, mix into plastic packets and keep records of the number of packets (i.e. sprayer fills used) and the area of coffee covered each day. This is an additional check. Check output with herbicide against the water calibration. Adjust walking speed to suit if necessary;

• Check that each operator is walking at a steady speed and is applying the herbicide properly. The operator must carry a marking stick;

• Use marking stick (preferably white) to indicate when the solution in the knapsack runs out. Commence spraying at this spot after refilling. Also spot check distances to confirm application is correct. It is preferable to run the knapsack until it is empty before refilling it  as this ensures that the spray solution does not become more concentrated at each filling; and

• Wash out knapsacks properly after use. Oil all moving parts and store away carefully.

·         When applying herbicides always walk straight down the coffee row.

• DO NOT spray round the plant stem as this will cause over‐application close to the mainstem.

• Ensure, when spraying down each row, that you do not get an overlap, which could double the application of herbicide close to the tree.

• Particular care must be taken when using residual herbicides on:
  • Very sandy soils;
  • Gravelly soils; and
  • Soils which tend to crack.

General checks on sprayers:

1. Ensure sprayers are not leaking;
2. Ensure nozzles are not blocked and are producing a uniform spray pattern;
3. Forward speed must be kept constant;
4. Make sure the height of the nozzle above the ground is constant to ensure correct swath width. (Tip: Use a spark plug on a string tied to the end of the nozzle as a marker);
5. Ensure sprayer contents are properly agitated (mechanically or by shaking);
6. Make sure that the chemical is not being applied to the foliage;
7. Do NOT spray under windy conditions especially when spraying young coffee;
8. Do NOT use herbicide knapsacks to apply insecticides, fungicides or foliar sprays;
9. Do NOT spill any herbicide in the land while mixing or spraying;
10. Use up any surplus herbicide by spraying on an area where weeds need to be controlled (e.g. around a fence or building); and
11. Do NOT throw herbicide around or waste it.

• FERTILIZATION

SOIL SAMPLING

Fertilization should initially be based on representative soil samples sent for analysis to a reputable soil laboratory familiar with coffee recommendations. Take a representative dry soil  sample  in winter (July) from within the rooting zone. 10 ‐ 20 Samples are taken after removing the leaf litter, from the area that the leaf samples were taken from. A core sampler or ‘V’ shaped hole should be dug to 20 cm depth. Clean out the bottom of the ‘V’ shaped hole and cut and lift out a 2 cm uniform slice on the spade, trimming off the edges with a knife to leave a 2 cm x 4 cm x 20 cm sample. Remove roots and stones and place in a clean plastic bucket. Mix sample. Collect 15 ‐ 20 sub samples per block. Mix all samples together and take half a kg of dry soil for analysis. Laboratories normally supply soil sample packets which are labelled according to the requirements of the laboratory.

After planting and trees are in bearing, leaf samples are taken at the appropriate time from bearing branches. This analysis determines the levels of nutrients in the plant and will indicate levels of deficiency or toxicity. Fertilization is based on ensuring the correct nutrient balance.

Different countries might use different criteria for leaf sampling. Ideally, a sample of at least 100 leaves should be taken from bearing branches in January or February. The sample comprises taking the third pair of leaves. Trees must be representative of the field.

The important nutrients in coffee are the following:

·         NITROGEN

A deficiency of nitrogen causes poor growth and a yellowing of the leaves on the bush. Nitrogen can be supplied in the form of compound fertilisers; Ammonium Nitrate or Urea. If Urea is foliar‐applied it must be spray grade as biuret, an impurity in urea, is very toxic to coffee. Symptoms are more acute than nitrogen deficiency. Initially mulch locks up nitrogen but later on it is released and a good source if applied correctly.

·         PHOSPHATE

Phosphate is essential for establishment. If the levels of available P2O5 are below 30 ppm, phosphate is required. Deficiency symptoms are not common. Phosphate is applied in compounds (blends of NPK) or as Single Super Phosphate (SSP), Double Super Phosphate (DSP) or as Di‐ammonium Phosphate (DAP).

·         POTASH

The fruit of the coffee bush takes up a lot of potash thereby making a deficiency of the nutrient a major problem, causing the leaf margins to become necrotic (brown then black) at the edges and to die off. Potash is usually supplied to the plant as compound fertiliser (e.g. 5:1:5 NPK) or as Muriate of Potash (MoP) also known as Potassium Chloride (KCl).

·         LIME

The soil and irrigation water should be checked for pH. Aquifers or boreholes with high  levels of calcium bicarbonate should not be applied to foliage as irrigation with this water increases the pH of the soil over time.

FERTILISER APPLICATION

Fertiliser applications should be based on the soil analysis reports of potting soil in the nursery and samples of the land prior to planting. General recommendations are given as a guide below:

IN THE NURSERY:

• Add lime if pH is below 4.5 (CaCl2 scale): 1 kg lime per 1 000 kg soil. Do not add lime if pH is above 5.0.
• Add a compound fertiliser in the ratio of:
• Approximately (6% N, 17% P205, 6% K20) at a rate of 3 kg per 1 000 kg soil.
• Thoroughly mix compound and lime (if required) into the soil by mixing a small quantity of measured‐out soil and fertiliser at a time.
• (1 cubic metre of soil is equivalent to 1 000 kg (one tonne soil).

NOTE: Cover the soil with plastic sheets in the event of rain which could hinder nursery operations.

• Top dress (but only after 3 pairs of true leaves have been formed).
• 30 g Ammonium Nitrate in 20 litres of water to 500 pots.
• (If pots smaller than 200 x 250 mm are used, this solution should cover 8 m2 in area).

In cases where potassium deficiency may occur:

• 20 g Ammonium Nitrate plus 50 g Potassium Sulphate should be added to 20 litres of water. These nutrients may be applied as a foliar feed providing that a recommended proprietary foliar mixture is used to avoid leaf burn.
• Top dressing should not be applied more than once per month during the winter months.
• 2 ‐ 4 applications are usually sufficient when reasonable potting soils are used.
• Sandy soils may require 4 or 5 applications. Correct watering is essential ‐ see irrigation application.

Soils with a high pH require an application of boron, as detailed below:

• Mix 40 g Solubor in 20 litres of water and apply evenly to the foliage after the first pair of true leaves has fully developed.
• 2 Sprays should be applied during the growing season.

IN THE LAND: FIRST YEAR (At or before planting out)

Rates are given in grams/tree assuming a 3.0 x 2.4 m spacing. 10 000/(3 x 2.4) = 1388 planting stations/ha.

Thoroughly mix in 250 g of a compound fertiliser containing the ratio of:

• 6N, 17P2O5, 6K2O per planting hole (equivalent to 350 kg/ha at a 3.0 x 2.4 m spacing).
• This is equivalent to 21 kg N, 60 kg P2O5 and 21 kg K2O.
• The size of the planting hole must be at least 45 cm x 45 cm x 45 cm.
• Add half of the amount (125 g) to the hole and mix with the soil in the bottom.
• Mix the remainder into the pile of top soil beside the hole.

Alternatively, broadcast 350 kg/ha of the same compound fertiliser and incorporate it deeply into the soil either by discing or ploughing before planting.

Top dressing with additional N is optional, based on condition of the soil, climate and plant.

SECOND YEAR IN THE LAND

Fertiliser		Months	OR
	Oct	Jan	Feb	Covas with more than 2 trees, light soils, in heavy rainfall areas, apply 4 equal applications
AN‐ Ammonium Nitrate (34.5%N) (g/tree    or Cova)	60 g	90 g	60 g	60 g
MoP‐ Muriate of Potash (60%K2O) (g/tree or Cova)	39 g	55 g	39 g	39 g

Apply both the AN and MoP in a broad band around or within the drip line of the tree on very sandy soils, avoiding the area close to the main stem.

Summary of N and K (Kg/ha) for second year in land from the table above for 1388 panting stations (cova’s)

Ammonium nitrate (AN) with 34.5%N

• applications, total of 210 g AN x 1388 = 291 kg AN/ha @ 34.5%N = 100 kg N/ha
• equal applications of 60 g AN x 4 x 1388 = 333 kg AN/ha @ 34.5%N = 114 kg N/ha Muriate of Potash (MOP) with 60% K2O
• applications, total of 133 g MOP x 1388 = 185 kg MOP @ 60% K2O = 110 kg K2O/ha
• equal applications 39 g x 4 = 156 g MOP x 1388 = 216 8 kg/ha MOP @60% K2O = 130 kg K2O

THIRD YEAR IN THE LAND

FOURTH YEAR IN THE LAND

NOTE: Urea (46%N) can be used instead of ammonium nitrate at three quarters of the rate (i.e. amount of ammonium nitrate x 0.75).

Urea must be lightly cultivated into the soil immediately after application if rainfall or irrigation does not fall within 1 or 2 days.

Other elements such as Sulphur, Magnesium, Boron and Zinc are also required and are added on the basis of leaf or soil analyses to the compound fertiliser, as a special coffee blend.

SUMMARY

Recommendations and chemicals change with time and it is important that you use this lecture as a guide. It is important to adhere to the label recommendations and purposes and to only use products registered for use on coffee.

Obtain varieties with resistance as it will save on the costs involved in obtaining and applying chemicals. Unfavourable weather often hinders effective spraying.

Disease incidence must be monitored regularly as a sudden outbreak can be difficult to control if it is not noticed earlier.

Climate change could impact on the disease situation as extremes cause changes in disease patterns and incidence.

The control of disease with chemicals is costly, timely and therefore efficiency of application and use of the correct dosages are important. Check the label for all product information and expiration  date.

In certain situations there may be a need to open up the tree by pruning or it may be preferable to ratoon or replant in situations where effective disease control is not possible.

Dr Michael St.J. Clowes and Peter Chard                    April 2013

1. DISEASES

The production of high yields is very dependent on efficient control of major diseases. The three major diseases are:

1. Coffee Leaf Rust (CLR) Hemileia vastatrix;
2. Coffee Berry Disease (CBD) Colletotrichum coffeanum; and
3. Fusarium bark/wilt disease (FBD) Fusarium lateritium var. longum (previously Fusarium stilboides).

These diseases are only controlled if the chemicals are:

• Applied at the correct time;
• Applied at the correct rate; and
• Applied so that there is proper coverage of the plant.

For effective disease control it is essential that you can:

• Recognise the various diseases;
• Apply the correct chemical at the right times; and
• Apply the chemical properly.

This is of great importance as effective and efficient disease control requires the implementation of  a disease control programme before the disease spreads and becomes widespread.

COFFEE LEAF RUST (CLR)

This disease was identified in 1869 in Ceylon (Sri Lanka) and reached Africa in 1883 and Brazil in 1970. CLR has had devastating results in many countries. Initially CLR resulted in a shift from coffee to tea production in many countries originally growing coffee. There are many strains of this disease and control methods are by using chemicals or selecting resistant varieties. Varietal resistance can break down over time. CLR defoliates trees.

CLR is easily identified by the yellow to orange spore masses which can be rubbed off and are easily noticed on the underside of the leaf. When scouting, always look under the branches forming the ‘skirt’ of the tree first, and then continue to the top of the tree.

Source: upload.wikimedia

Occurrence	It is widespread throughout Africa and there are different races of this disease.
Control: Preventative; Chemical	Copper products (e.g. oxychloride) are applied as a preventative spray before the disease is widespread or serious.   The first spray should be applied before the rains, followed by monthly sprays during the rains.
Curative	If an outbreak of leaf rust occurs, then a curative spray (one that kills the leaf rust) (e.g. triazole systemic fungicide such as Bayleton) must be applied. Two sprays 6 weeks apart are needed to control leaf rust.
Resistant Varieties	Some varieties are resistant to some of the major types of rust e.g. K7, S.agaro, Geisha and Ruiru 11. The Hybrid de Timor resistance has been conferred to Caturra to produce a range of Catimor varieties and to Ruiru 11 in Kenya.

COFFEE BERRY DISEASE (CBD)

A virulent strain of this disease was discovered in 1922 in Kenya and has continued to spread within Africa and currently poses the greatest threat to the industry. CBD challenges the economic viability of the industry under conditions of prolonged wet and cool weather and has resulted in the decline in the area grown to coffee.

Source: plantwise

This disease is mainly spread by infected seed and can attack different parts of the plant.

Flowers Berries         Leaves	Infection produces brown lesions on the white flower petals.     A small sunken dark brown or black lesion on infected berries continues to develop to invade the entire berry. The bean (seed) is usually destroyed.   Infected ripe berries have brown sunken lesions covered with minute black dots.   Brown lesions may occur on leaf margins.
Control: Chemical	Once CBD breaks out, chemicals are used to control the disease during fruit development (expansion to ripening). Multiple flowering which results from CBD infection means that flowering can occur over a long period of time. Cool wet weather suits the development of the disease and hinders spraying operations.
Resistant genotypes	Rume Sudan and Hybrid de Timor have different genes for resistance to CBD, and Ruiru 11 developed in Kenya has resistance to CLR and CBD.
Chemical Control Programme	Copper oxychloride (11 kg/ha) or cupric hydroxide (8‐9 kg/ha), Anilazine or Chlorothalonil at 5 kg/ha. One can mix half rates of 1 of the copper products with 1 of the organic products above. Chemical lables must be checked for recommendations. This must be integrated to facilitate CLR and Fusarium programme.

FUSARIUM BARK DISEASE (FBD)

This disease almost devastated the Malawi and Zimbabwe coffee industry in the 1970s. It is mainly spread by infected seed, insects, movement of people and pruning tools. It can attack different parts of the plant.

Source: cd3wd

Seedling Blight	Infected seed produces matching lesions (dark brown/ black patches) on the cotyledon leaves which fail to unfold and the leaves, stem and seedling dies.
Collar Rot	Infected seed also produces collar rot. Symptoms become apparent between March and May when trees are carrying their first major crop. The leaves will wilt and turn yellow. Scraping off the bark close to ground level will reveal a dark brown to black lesion just below the bark. (Healthy bark just below the surface would be light green in colour.)

Signs of secondary infection are:

Berry Blight (gives rise to seed infection)	Infected berries have a sunken dark brown lesion at the stalk end and normally carry a mass of pink/white spores.
Branch Blight	The entire branch (primary, secondary or tertiary) wilts, and leaves remain attached to the branch, turning a chocolate brown colour. Isolated branches on a tree are normally affected with pink/white spores, often evident at the base of the infected branch.
Sucker Infection	This is the most common sign of Fusarium infection on older trees. Suckers arising from the mainstem are discoloured at their base and often contain a mass of pink/white spores and the sucker eventually dies. Sucker infection is common when trees with mainstem infection (scaly bark or collar rot) are rejuvenated. Mainstem infection prevents successful rejuvenation of infected trees.
Scaly Bark	This is common on older trees and is a secondary infection of the mainstem and can lead to sucker and branch infection. An elongated brown/black lesion just below the bark is characteristic of scaly bark which also becomes scaly on old trees.
Control
a)   Seed	This must be free of Fusarium infection Obtain seed from a registered seed producer. Treat  seed  before  planting  in  the  nursery  with  1  g  Benlate       or

	Benomyl per 1 kg seed. Thoroughly mix seed and chemical (powder) together in a plastic bag.
b)   Seedlings	In order to prevent any chance of secondary infection within the nursery, strict hygiene measures must be applied and enforced. Captafol proved effective as a protective spray but has since been removed from the market due to its residual toxicity.
c)    In the land	If precautions as in (a) and (b) above have been taken and no Fusarium noticed and coffee plants growing in adjacent areas are  free of Fusarium, only begin a routine spray programme once the  first signs of the disease are noticed. To control cercospora, 4 sprays of copper oxychloride (1 before, 1 after and 2 during the rains) will be required.
	Rates: 500 g/100 litres water. Equates to 10 kg/ha
*Note	Bayleton or other suitable products would only be used if an  outbreak of Leaf Rust occurred, because it is not effective against Fusarium.
d)   Resistant Varieties	S.agaro and Geisha seed collected from Fusarium‐resistant parents have a degree of resistance to Fusarium.
e)    Insect Transmission	Insects appear to be largely responsible for the spread of the disease in an infected plantation which means that good control of insects is necessary to reduce the spread of FBD.
f)     Field Hygiene	Infected material should be removed from the plant immediately when signs of disease are first noticed.
Sign	Plant Part Removed
Collar rot	Whole tree
Branch Blight	Branches
Seedling Blight	Seedling (and possibly adjacent healthy seedlings)
Berry Blight	Fruits
	Disinfect any equipment used including hands
	with household disinfectant when going from one tree to another
	Large wounds should be painted with a tree‐sealing compound.  (e.g.
	Steriseal)

CERCOSPORA ‐ LEAF AND BERRY BLOTCH (Cercospora coffeicola)

Infected leaves contain grey/white lesions surrounded by a brown border.

Infected berries contain a grey/black sunken lesion which develops on ripening berries causing premature localised ripening and berry shed.

The copper oxychloride spray programme for leaf rust prevention controls this disease.

On varieties resistant to Leaf Rust and where no Fusarium occurs, a copper oxychloride spray before and after the rains and 2 during the rains is recommended.

MINOR DISEASES

Warty Berry Disease

Small greyish scabs and warts develop on the coffee berries which then turn brown in colour. The beans inside wither and rot and under humid conditions a loose grey spore mass may develop. Control measures are not usually necessary.

Weak Spot

Small yellow spots are surrounded by a brown hole. Control measures are not required.

Sooty Mould

Sooty mould develops on leaves, berries and twigs which are attacked by scale or aphids. This mould is not parasitic and is eliminated by controlling the insects, including ants.

Root Rot (Armillaria) (See Tea Lectures)

Affected plants wilt and turn yellow and the tree may die. A white mat of fungus can be seen on the roots (inside the bark) and at the base of the tree which has a smell characteristic of mushrooms. Infected plants should be removed and re‐planting should only be done after 2 years. There may be chemicals that one can use but they must be registered. During the initial preparation of coffee   lands all indigenous trees should be ring barked at least 2 years before planting the coffee.

Suberized Berry

Brown corky areas develop on the berry. No control measures are necessary.

CHEMICAL APPLICATION OF FUNGICIDE:

• As copper oxychloride is applied as a preventive spray, there must be good coverage of the leaves, (lower surfaces, especially for Leaf Rust) and the branching framework (especially the mainstem for Fusarium).

• It is important to obtain the coverage before the disease is serious and, in the case of leaf rust, before the onset of the rains.

• A full cover spray means that spraying should not be to run‐off but should stop before any noticeable run‐off occurs.

• Droplets are so small that they are not easily seen with the naked eye.

• The spraying machine should be properly calibrated and contain the correct amount of chemical in the correct amount of water. Forward speed and pressure must be correct.

• Nozzles wear out with use and should be replaced regularly.

• Operators must be properly trained in the use of the spraying equipment.

• The labels must be carefully read and the directions followed as printed on the label.

• It might be necessary to open up trees to get penetration of the spray if knapsacks (low pressure) are used. A mistblower is much more effective in getting the required spray penetration.

• Calibrate the knapsack using the time taken to spray a given number of trees effectively. See calibration for herbicides in the lecture on Weed Control. Time taken to spray a tree effectively is used to calibrate the sprayer. Test this in practice with water before calibration starts.

• COMMON PLANT DISORDERS

Only the 2 most common examples are given to indicate how dangerous it is to attempt to correct the symptoms without knowing what the real causes of the symptoms are.

SYMPTOM: NECROSIS (blackening of the leaves) Possible causes:

1. Excessive fertiliser application (especially nitrogen). Common in the nursery and the first year in the land.

• Foliage has been contaminated with fertilizser (especially ammonium nitrate) when:

1. It was not washed off in the nursery.
   1. Application was made during wet conditions or when there was dew on the plant. The plant has been contaminated by the applicator’s hands or clothes or by  improper placement of fertiliser.

• Potassium deficiency (necrosis of the leaf margin) especially on fully expanded leaves.

• Sunscorch which tends to be brown rather than black necrosis.

• Frost damage which tends to be brown rather than black necrosis.

• Gramoxone (herbicide damage). Common on young tress when sprayed under windy conditions or applied too close to the plant.

SYMPTOM:  YELLOWING OF THE LEAVES

Possible causes:

1. Excessive sun in the nursery:
   1. During very hot periods; and
   1. If shade is removed too quickly during the hardening off period.

• Waterlogging:
  • Pots not properly perforated;
  • Soils very heavy and watering too frequent; and
  • Pots with holes in the bottom or side packed too close together on a soil with poor drainage.

• Nitrogen deficiency:
  • Poor sandy soils have been used;
  • Leaching has occurred; and
  • Inadequate nitrogen has been applied.

• Root damage:
  • Eelworm;
  • White grub;
  • Root mealybug; and
  • Armillaria.

• Stem damage:
  • White borers;
  • Yellow headed borers;
  • Black borers; and
  • Dusty surface beetle.

• Physiological dieback:

Tips begin dying back, fruits also turn yellow and then black, and mature leaves and  fruits are shed. Causes are:

1. Inadequate irrigation;
   1. Nutritional deficiency; and
   1. Defoliation from leaf rust, leaf miner, frost or hail damage.

• Sulphur deficiency; and

• Biuret toxicity from foliar spraying urea which was not spray grade.

WHEN THESE SYSTEMS OCCUR

Do not try to correct the situation. A consultant, extension officer or someone with experience should be consulted to accurately determine what caused the systems to develop.

SUMMARY

It is important to be able to recognize the pest, the damage it does and the threshold levels for its control based on cost benefit. Early control of an outbreak is dependent on good scouting, effective spraying and quick follow‐up, based on the life cycle of the pest and the climate and can take time to eradicate an outbreak.

Use only registered chemicals and strictly follow the label instructions.

For sustainable pest control an integrated pest management programme using the less toxic chemicals and systemic chemicals with more selective activity is desirable.

Broad spectrum killing encourages other pests to become of economic importance. It is good practice to alternate the use of certain chemicals to try and avoid the development of resistance.

Replanting on a cycle of 8 ‐ 12 years has the advantage of ‘zeroing’ out pests after each crop cycle in hotter conditions which favour pest build up.

Dr Michael St.J. Clowes and Peter Chard                    April 2013

1. PESTS

Coffee is attacked by a wide range of insect pests. It is important to control coffee insect pests as they can do damage to:

• Leaves;
  • Fruits and flowers;
  • Stems and branches; and
  • Roots.

The efficiency of insect pest control is important because over‐application or incorrect timing of insecticide application is:

• Wasteful and costly; and
  • Damaging, because parasites are killed which assist in keeping insect populations under control.

It is clear that regular scouting for insect pests in each land is necessary. Scouting should he carried out:

• Twice per week in the hotter months (August ‐ April); and
  • Once per week in the colder months (May ‐July).

For effective scouting, coffee scouts must be able to identify insect pests and the damage they cause. It is important for the scout to have the knowledge of the following for each pest:

1. Common insect pest life cycles.
2. The stages in the life cycle most commonly seen.
3. What this stage looks like?
4. On what part of the plant it is most commonly seen?
5. What damage is caused?
6. When the damage occurs?

An effective coffee scout can make decisions on:

• Whether to use chemicals to control the insect problem; and
• The chemical to be used ensuring that the chemicals are properly applied.

Life Cycles:

1. Egg                                 larva                                 pupa                                 adult
2. Egg                                           nymphal stages*                                          adult
3. *Similar to adult but not as developed

THE MAJOR PESTS OF COFFEE AND THE PLANT PARTS THEY ATTACK

Pest Insect	Stage most Usually Seen	Plant Part Affected
Leaf Miner Stinging Caterpillar Red Tortrix and Green Tortrix Cotton Semi‐looper Giant Looper	Moth, larva, pupa Larva Larva Larva Larva	Leaf Leaf Leaf, berries and tips Leaf Leaf
Jelly Grub	Larva	Leaf
Bagworms Snout Beetle (Systates) Mealybug Scales	Pupa Beetle Mealybug (sooty mould) Scale (sooty mould)	Leaf Leaf Leaf, berries and stem Leaf, berries and stem
Dusty Brown Surface Beetle	Beetle	Mainstem
Black Borer	Beetle	Mainstem
White Borer	Beetle/larva	Mainstem
Yellow Headed Borer	Larva	Mainstem and branches
Antestia Bug	Egg and Bug	Flowers, beans and branch growing points.
Berry Borer	Larva	Fruit
Fruit Fly	Larva, fly	Immature fruits
Root Mealybug White Grub	Mealybug Larvae	Roots Roots

The pictures below provide some help in terms of identification of major pests.

Figure 1: Snout Beetle                                            Figure 2: Antestia Bug

Source: farm9.staticflickr                                                Source: ispot

Figure 3: Fruit Fly

Source: mrjacksfarm

COFFEE LEAF MINER

This is the most important pest of coffee. Small groups of flattened eggs are laid on the upper leaf surfaces, hatching after 1 ‐ 2 weeks. The young larva enters the leaf through the bottom of the egg and proceeds to feed on leaf tissue under the surface. It is most susceptible to insecticides at this stage. The larva takes 2 ‐ 5 weeks to reach maturity and is about 8 mm long. It then exits the mine through a slit and lowers itself to a lower leaf or dead leaves on the ground. It pupates into an H‐ shaped white cocoon about 6 mm long. The very small white moth, about 3 mm long, emerges 1 ‐ 2 weeks later, living for up to 2 weeks but lays most of its eggs during the first few days after emergence. To scout for the moth the tree should be disturbed to observe the pests flying out.

Damage:              The  mining  activities  of  the  larvae  produce  irregular  brown blotches on leaves and results in leaf drop. Severe damage occurs within a very short period of time when infestation levels are high.

Occurrence:       Widespread on coffee of all ages.

ANTESTIA BUG

This is almost as important as leaf miner and more difficult to control. A few insects can cause a lot  of damage as it attacks the fruit. See Table of Thresholds. White coloured eggs are laid in groups of 12 on the underside of the leaf and can be parasitised. Eggs hatch after 10 days into nymphs, like young adults with wings not fully developed. Nymphs live for 3 ‐ 4 months developing into mature, shield‐shaped adults with brown, orange and white markings similar to ladybirds.

Antestia bugs like shade and are difficult to see. Scout either early in the morning or late afternoon.

1 ‐ 2 insects per tree warrant spraying.

Damage:        Blackening of flower buds;

Shedding of immature berries; Rotting of beans within the cherries; Fan branching;

Discolouration of bean; and Parchment cracks – zebra striping.

Occurrence: Widespread

BAGWORMS

Larvae live in cones made of leaf or twig fragments suspended from the underside of the leaf. Bagworms are difficult to control with chemicals and handpicking should be considered.

Damage:       Characteristic round holes in leaves (like jelly grub)

Occurrence: Not common

BERRY MOTH

Eggs are usually laid singly on or near green berries. Hatching takes about 1 week to produce reddish transparent caterpillars with faint black markings which bore into the berries near the stalk.

The larva spins a web round the berries. Larva is fully grown in 2 weeks when it drops to the ground to pupate. The moth is small with a 13 mm wingspan and golden brown in colour.

Damage:        Damages berries, usually in clusters; and Damaged fruit turns yellow, then black

Occurrence: Becoming more widespread

BLACK BORER

Outbreaks tend to occur more frequently in coffee growing adjacent to indigenous trees. The beetle is black and approximately 20 mm long, bores a 6 mm diameter tunnel upwards in the mainstem.

Damage:      Sawdust and frass (droppings) on the ground indicate tunnels have been formed and several beetles may be found in one tunnel

Occurrence: Not widespread, but causes considerable damage

WHITE BORER

Eggs are laid beneath the bark just above ground level. The egg hatches in about 3 weeks to produce a larva which bores downwards just under the bark and often ringbarking the tree. It penetrates deeply into the wood at about ground level (or just below).

The larval stage lasts about 20 months and pupation occurs within the tree trunk. Adults emerge from the 10 mm diameter hole after 2 ‐ 4 months. The adult is large, 30 mm long and brown with white markings. The males have very long antennas and emerge with the onset the rains. If the rains are late a high population of adults can occur and might warrant collection by hand.

Damage:             Wood shavings extricated from the bark near ground level. Leaves on ringbarked trees turn yellow and these trees need to be removed

Occurrence:                       Not widespread, but can cause considerable damage in some years

YELLOW HEADED BORER

Eggs are laid near the top of a branch. The larva bores into the shoot causing it to wilt. It bores down the primary towards the mainstem making ‘flute holes’ then continues down in the mainstem. The larva pupates after approximately 10 months within the mainstem, close to ground level. The pupal period lasts 2 months. Adult beetles are about 25 mm long with long black antennae. The body is brown with yellow markings on wings and thorax. Adults emerge during the rains.

Damage:             A row of evenly spaced holes down one side of the branch and mainstem known as ‘flute holing’ is characteristic.

Insect causes wilting of tips on primary branches which are then prone to breakage

Occurrence:       Not widespread but may cause considerable damage when it occurs

DUSTY SURFACE BEETLE

Eggs are laid in the soil and are yellow‐white in colour approximately 1mm in diameter. They take about 2 weeks to hatch. The larvae, which inhabit the soil are known as false wire worms and sometimes attack coffee roots. They pupate in the soil. The adult is oval shaped, flattened and 9.5 mm long dusty brown in colour with longitudinal ridges on wing covers. They feed at night and hide by day.

Damage:              Severe damage usually only occurs during the first year in the land, when the stem at ground level is often completely ring‐barked

Occurrence: A sporadic pest in cooler areas, but serious where arable crops grow in hotter areas. Attacks occur when coffee is mulched and where insecticides have not been used to control these pests. It is not a sufficient reason for not mulching as the pest is easily controlled with a chemical drench.

FRUIT FLY

Eggs are inserted into the pulp of mature fruits where they hatch into white maggots. Over‐ripe cherries invariably contain 1 or more maggots which are 8.5 mm long when fully grown. Maggots pupate in the soil. The adult is an orange brown fly 4.5 mm long with mottled wings about half the size of a fully grown housefly.

Damage:              Crop loses  occur  only when the eggs  are inserted  into  expanding fruits from a late flowering. These fruits tend to drop and, when squeezed, a drop of moisture is produced where the egg was inserted into the fruit.

Occurrence:       Commonly found invading ripe fruit where it does not cause any damage.

Loss in crop is likely to occur only on late flowerings.

JELLY GRUB

White scale‐like eggs are laid singly on both sides of a leaf. The larva is oval, bluish green, slug‐like and when mature, is 13 mm long. The larval period lasts 6 ‐ 8 weeks. Pupation occurs in a white silken cocoon, 6 mm long, spun in a fold of a leaf or between two leaves.

The adult emerges after at least 3 weeks but is seldom seen. It is brown with darker patches on the forewing with a wingspan of 25 mm.

Damage:        Characteristic round holes through the leaf (like bagworms)

Occurrence: Common in the cooler areas

COTTON SEMI‐LOOPER

Eggs are shaped like a sea‐urchin, pale yellowish green in colour with fine radial ribs. Eggs are laid singly on the under surface of the leaf and are about 0.6 mm in diameter. The larva is a green looper with 3 pairs of legs at the front and back with no legs in between.

The legless area produces the loop as it moves. A white lateral line runs through the spiracles and a series of wavy white lines run down the back. A white silken cocoon is spun, usually in the fold of a leaf with the pupa visible within the cocoon. The pupa is green turning dark brown before the adult emerges. The adult has brown forewings washed with bronze with two conspicuous gold spots. At rest the wings are held tent wise over the body with a characteristic pair of tufts of hair on the thorax. The moth is very active during the day.

Damage:       Severe  leaf  damage  can  occur  which  leads  to  defoliation  if  the  pest is not controlled.

Occurrence: Sporadic but is becoming more common in some areas.

GIANT LOOPER

Pale blue‐green oval eggs are laid in crevices in the bark. The larvae are typical loopers, pale grey to dark brown and resemble twigs (50 mm long). The mature larva drops to the ground and pupates in the soil. The pupa is shiny brown and 19 mm long. The adult moth is grey with a lot of dark grey marking with a wingspan 50 mm long.

Damage:             This pest causes severe leaf damage. Outbreaks have been associated with the excessive application of parathion

Occurrence:       Not common but some serious outbreaks have occurred

MEALYBUGS

There are a number of species which are covered with a white mealy waxy secretion with longer filaments to the side and rear of the insect. Colonies of mealybugs can be found between clusters of berries, flower buds or on new growth. They secrete sticky, transparent honeydew on which a black sooty mould will grow. Ants feed on the honeydew and generally accompany the mealybugs.

Eggs are laid in batches of up to 200 in a waxy ovisac behind the female. The young mealy bugs  which hatch out are flat, oval, and brown with 6 short legs and no wax on their bodies. They crawl  up the tree to feed on plant sap and pass through a number of nymphal stages. At each stage, they become larger and waxier.

Females which can move are fertilized by winged males (Note: male and female differ).

Damage:             Mealybugs  tend  to  smother  the  affected  parts  of  the  plant  as  they  are covered in honeydew and sooty mould.

Occurrence:       Increasing in importance in localised areas. Often isolated patches develop within a field making good scouting necessary.

ROOT MEALYBUGS

Generally similar to mealybugs described above.

Damage:              White mealybugs which invade the roots are covered with a    whitish fungal net. First signs are usually yellowing and wilting of leaves.

Occurrence:       Not common

SCALES

There are many types and are referred to by colour and appearance for example black, brown,  green, white and waxy.

Adult females are immobile and found concentrated along the leaf veins and tips of green shoots. They produce honeydew and are often covered with sooty mould. Nymphal stages are mobile and have 6 short legs.

Damage:             Heavily  infected  branches  lose  vigour and should  be  removed and placed under the tree to allow the natural predators to build up.

Occurrence:       Not common

SNOUT BEETLES (Systates)

Eggs hatch in the soil to produce white legless grubs which feed below the soil surface. The adult beetle is a snouted weevil 8 mm long which feeds on the edges of leaves to produce characteristic indentations. The insect hides during the day.

Damage: This pest tends to prefer a shaded environment produced by mature trees. Characteristic snout beetle damage is indentations (bites) around the edges  of a leaf

Occurrence: Isolated serious outbreaks have occurred in nurseries and young coffee trees in the land

STINGING CATERPILLAR

Small groups of eggs like tiles are laid on the lower leaf surface and hatch in about 10 days. The young larvae are white but turn green later, with another species being green and brown. Hairs on the body sting when touched. The mature larva spins a brown, brittle cocoon on the leaf or more commonly the main stem. The adult moth has green forewings with a brown border with yellow  hind wings. Wingspan is 32 mm.

Damage:         Leaves eaten and heavy damage can occur

Occurrence:  Widespread in the Eastern Districts of Zimbabwe

RED AND GREEN TORTRIX

Eggs are yellow‐orange in colour, flattened and laid in large groups on the upper surface of leaves. They overlap in the same way as fish scales. The eggs hatch in 8 ‐ 12 days.

Green Tortrix larva are green with a black head and thoracic shield. Red Tortrix larva are reddish brown with dark brown stripes.

These young larvae are very active and take up a position between touching leaves. They prefer young growth which they can use to tie together with silk. Alternatively they may bore into the tip of a shoot and form a “nest” by webbing the wilting leaves together. Cherries may also be bored in which case the tunnel is lined with silk. The larval stage lasts about 1 month and pupation occurs within the nest. Adults are brown, shield‐shaped moths with darker markings and 6 – 13 mm long. Eggs are laid on the day the moths emerge.

Damage:              Leaves,  shoot  tips,  and  berries  are  covered  in  thread  and eaten causing considerable damage when populations are heavy.

Occurrence:       Becoming fairly widespread.

WHITE GRUB

The adult beetle feeds on the foliage of several indigenous trees. The larval stage is a ‘C’‐shaped whitish grub with a brown head and 3 pairs of legs. It lives underground and feeds on the roots of many plants including Napier (elephant) grass and coffee.

Damage:             Can cause serious root damage particularly to young coffee and Napier grass.

Occurrence:       Sporadic pest which can cause severe damage in some years.

NEMATODES

There are three main types of nematodes:

Rootknot	Meloidogyne species;
Root Lesion	Pratylenchus species; and
Burrowing	Radopholus similis.

The nematode is not readily observed although the damage it causes may be obvious.

Damage	Rootknot	Swelling, lumps on roots
	Root Lesion	Lesions
	Young plants are most likely to be affected;Affected plants turn yellow and wilt; andSoil and root samples should be collected for analysis by a Plant Protection Laboratory.
Occurrence	Rare and are limited to nurseries.

SLUGS AND SNAILS

Baits should be used to control these pests.

• CONTROL MEASURES
  • Only apply insecticides when required. They should never be applied as a routine measure with fungicides.

• Soil‐applied granular systemic insecticides (e.g. Di‐Syston and Solvirex (disulfoton)) encourage biological control because they do not harm parasites and predators. They are only active in controlling pests about 6 weeks after application. They do not control antestia bug. Actara (thiamethoxam) has action against antestia if applied twice in the season in Zambia.

Soil‐applied systemic insecticides need to be applied evenly around the drip line, incorporated lightly into the soil and watered in. Trees must be growing actively. Application is usually before the rains with irrigation (e.g. August/September or once the rains set in). Chemical sprays are usually used to control insects when systemics are not effective. Depending on chemical and climatic conditions persistence of a systemic may last up to 20 weeks or longer from time of application.

Ensure that the correct application to harvest interval is always adhered to.

Contact chemicals often need to be applied again within 10 ‐ 14 days to cover the stages in a life cycle. The label will indicate the correct interval between sprays.

Actara (thiamethoxam) is a systemic insecticide applied as a foliar spray (lower rate) or to the soil. It has given effective control of leaf miner (one application/year) and antestia (2 applications/year) but should not be applied within 3 months of harvest.

• Chemical banding of the mainstems with Dursban (chlorpirifos), 0 ‐ 60 cm from ground level, should be carried out as a routine in August/September as a precaution against:
  • White Borer; and
  • Ants, which encourage scale and mealy bug infestation.

Chemical sprays should be applied as indicated after scouting. A range of chemicals is available and the choice will depend on insect spectrum, spectrum of activity, cost, toxicity and method of application. The following economic thresholds are suggested as general guidelines for coffee:

Age of Coffee (Years in Land)	Pests counts/tree which would warrant spray
	Leaf Miner	Antestia	Caterpillars e.g. Tortrix/Stinging caterpillar/ Loopers etc.
1st	2 ‐ 5	1 ‐ 2	1
2nd	5 – 10	1 ‐ 2	2 ‐ 5
3rd	10 – 20	1 ‐ 2	5 ‐ 10
4th and older	20 – 40	1 ‐ 2	10 ‐ 20

TIMING OF SPRAYS:

• Leaf Miner  1 week after threshold level (or moth peak) has been reached and repeated 3 –  4 weeks later.

• Antestia  As soon as 1 – 2 nymphs and adults per tree are observed.

• Caterpillars Preferable spray when larvae are very small and chemical control is most effective.

• Spot spraying can be carried out when localised insect outbreaks are noticed.

• Always read the label regarding rates, dilution, pests controlled, permissible interval  between spraying and harvesting berries and compatibility with other chemicals.

• Ensure that all precautions with regard to protective clothing, masks, gloves and handling of the chemicals are followed.

• SCOUTING PROCEDURES

Scout diagonally across the land in both directions as well as down each side of the land as pests tend to come in from surrounding bush areas, often in the direction of the prevailing wind. Stop and examine every twentieth tree looking closely at all the trees you walk past for possible signs of damage (e.g. wilting tips, yellowing of leaves, sawdust, etc). Trees showing signs of possible insect damage should be examined.

After the general scouting of the land you will know:

• What pests there are on the land;
  • Whether they occur throughout the field or a localised area;
  • Areas where particular pests appear to be concentrated; and
  • Whether these pests are approaching or have reached a threshold which necessitates control measures being taken.

Follow up the general scouting with a more detailed scouting specifically for pests which are likely to need controlling. Select 20 trees in the area where the pest situation is worst (if the problem seems to be localised), or select trees where there is evidence of the pest. Record pest levels and use the

threshold guide to determine whether you need to apply control measures which may be either a

spot or general treatment.

More frequent scouting will be required if there appears to be a pest build‐up. Pockets in the land where, for example, leaf miner tends to build up should be marked and scouted regularly for an  early warning sign. Spot spraying should be considered in preference to a general spray of the whole field. Earmark areas for soil applied systemic treatment the following season.

Scouts are advised to keep notes on each field and to graph insect numbers recorded on each occasion.

The most efficient scouting is done in the early morning, the late afternoon or on overcast days.

SUMMARY

Irrigation is essential in the hotter growing areas and to overcome the impact of drought in the cooler areas. It is costly and a thorough risk benefit analysis is required before any plans are implemented. All other factors must be to the required standard if the full benefits of irrigation are  to be realised. The scheduling method is done with the use of an auger, observation and common sense to help complement the method.

Harvesting and processing on time and to standard are essential if the benefits to all the hard work  in the field are to be realised. Attention to detail, regular moisture checks, keeping track of the weights are all equally important in optimizing returns.

It is important to know your market and to meet its requirements.

Dr M. St.J. Clowes and Peter Chard                       April 2013

1. IRRIGATION

Irrigation is necessary for coffee grown in the hotter lower‐lying areas. Irrigation is also often of benefit in the highlands to overcome droughts which are becoming more common. It is important to obtain water rights for the amount of water one requires. The design of the irrigation system must meet the plant’s requirements during the hottest period of the year. Watering (irrigation) is also required for nurseries.

Proper irrigation control is required to:

• Maximise the growth of the trees and prevent the development of stress and dieback;
  • Minimise soil erosion in the plantation;
  • Prevent excessive leaching of nutrients from the soil; and
  • Prevent the accumulation of salts near the soil surface which will produce a brak or alkaline soil.

IRRIGATION IN THE NURSERY

After the seed are planted, the soil in the pots or sleeves should be kept moist by applying a good watering every 3 days. The soil surface should be covered by sand or grass mulch which prevents it from drying out too quickly.

After the seed has germinated, less frequent watering is required. The pots should be well watered and not to be allowed to dry out. 2 – 3 Good waterings per week are recommended during summer and once a week during winter. Small pots or sleeves need to be watered more often than large pots. The pots must be able to drain properly; and should never be allowed to become soggy at the bottom on the day after watering.

Watering should be done using a hosepipe with a fine oblong rose which gives small droplets of water at a low pressure. Water should be applied evenly over the seedbed or area of pots. Plants at the side of a bed often get less water than those in the centre.

IRRIGATION IN THE LANDS

Coffee is a perennial crop and a wide range of irrigation methods can be used on the crop. Irrigation systems can be fixed or portable and can apply water beneath the canopy directly to the soil around the stem of the tree or applied by overhead sprinklers. The main systems used for the irrigation of coffee are the following:

UNDER‐TREE SYSTEMS

Provided they are efficient, these systems will use up to 25% less water than the overhead systems. The labour requirement will depend on whether the pipes have to be moved frequently or are a permanent fixture. On some soils and where there is no mulch water may run off rather than into the soil. Soil can be built up to make basins round the outer drip line of the tree to help conserve water.

• Dragline Sprinkler System ‐ A small sprinkler mounted on skids attached to a long flexible pipe with a small diameter. The hose is attached to the main line and the sprinkler moved around the plantation. It is one of the cheapest systems and has a low labour requirement.

• Microjet System ‐ This requires a permanent mainline with spray lines leading off to each row of trees. The spray lines are of small‐diameter, black polythene pipe, and have plastic jets for each planting station. The number of microjets for a 2.4 m x 3.0 m spacing is 1388 microjets/ha.

The jets produce a low‐angle spray with a wetting diameter of 3 – 4 m and will apply about 14 mm of water per hour, so the maximum amount of water required can be applied in 5 hours. In order to reduce the size of the pump, the spray lines do not all run at once, and any 1 spray line would be used only once a week at the most. This system is expensive but has a very low labour requirement and uses water efficiently.

• Trickle Irrigation ‐ This system has a mainline from which feeder lines are run along each  row of coffee trees. At each tree, a small hole in the pipe allows water to trickle onto the ground. The system is expensive to install but the labour requirement very low. Water has to be filtered to remove any solid matter that may block the trickle holes in the pipes.

• Hose Basin Irrigation ‐ Large basins are formed under each tree, covering the area shaded  by the canopy of the tree. Water is run into the basins from hoses attached to permanent or portable mainlines. Single or multiple hoses may be used. The hoses can be polythene pipe  or garden hose. By only using one hose, up to 20 litres of water can be applied to a tree in a minute. The hose has to be moved frequently. This system is particularly good for young trees, cheap to install, but the labour requirements can be very high during peak irrigation periods.

• Overhead Sprinkler Systems ‐ These systems are simple to operate and their performance checked more easily than the under‐tree systems. They can operate on a 24 hour‐a‐day basis (at peak requirement periods) and their costs are comparable with other systems. There is more water use under this system due to evaporation losses both in the air and from the soil surface between the rows of trees. The pressure required to pump the water through the sprinklers is higher than for low volume systems so a bigger pump is needed. Centre pivot systems are used for larger estates and must be properly designed for the soil, crop and climate.

• Portable System ‐ A main line is laid through the plantation and portable lines with  sprinklers are connected to valves at various points along the line. The lines are moved through the plantation at regular intervals. This system is very flexible, but requires a number of skilled labourers.

• Solid Set System ‐ Both the main line and sprinkler lines are buried in permanent positions and riser valves are spaced along the sprinkler lines at the required spacings. Only 1 or 2 sprinklers operate from each line at a time. They can be easily moved (hop along from one position to the next); therefore the labour requirement is not excessive. The cost of  installing this system is about the same as that for a portable system.

The three main requirements of any irrigation system are:

• The system must be able to supply sufficient water when the requirement is greatest. This is when the evaporation rate is at its highest, usually before the rains. The amount needed at peak is likely to vary between 6 mm – 9 mm per day from the cooler highlands to the hotter lowlands. Irrigation efficiency must be taken into account and can vary from about 60 ‐ 70% (furrow), 70 ‐ 80% (overhead) and 80 ‐ 90% (drip) and will obviously deteriorate through wear and tear over time.

• In the hotter areas the system must be able to supply water throughout the whole year as rainfall can be erratic. Where borehole water is used it should not be a problem. But where water is supplied from a dam, the capacity must be large enough to supply sufficient water throughout the dry winter months.

• The irrigation should be controlled so as to achieve the maximum benefit. A portable overhead system can also be used to irrigate other crops, but most of the other systems can only be used on the coffee plantation.

A rain gauge is used to measure the rainfall which is applied to calculate the water requirements on  a plantation. An evaporation pan is used to measure both the water lost by evaporation from the ground and the transpiration from the crop for the plantation area. Every plantation should have a rain gauge and evaporation pan. There are crop factors based on canopy cover for the different ages of coffee that are used in the calculation.

Rainfall and evaporation and the stage of crop growth are used to develop a profit and loss account for water to determine when to irrigate. This information should be supplied with the  commissioning of the scheme by the irrigation engineers.

The following information can be used as a guide to irrigation and can be backed up by the use of a soil auger to see if irrigation is required by the soil.

Dryland planting before the rain:

Before planting	10 litres of water per station or plant;
Immediately after planting	5 litres of water per station or plant; and
Every 4 – 10 days	3 – 5 litres of water per station or plant.

In the hotter periods the interval should be 2 ‐ 4 days between irrigation until the plant has started to grow after transplanting.

With sprinkler irrigation, apply 50 mm water before and 25 mm after planting, followed by 25 mm every 7 ‐ 10 days until the rains begin.

If the plants are being planted out into basins, these should be small in diameter but fairly deep. The water applied then penetrates the ground around the roots and does not flow away from the plant.

With any irrigation system the amount of water being applied should be checked. Trickle systems  can be checked by the use of a timer and overhead systems by using buckets or rain gauges. All systems should be checked regularly to make sure that there are no leaks in the pipes, furrows or canals and that all sprinklers are working properly. The pressure gauges should be checked to ensure that the water pressure within the system is correct.

• HARVESTING

Coffee is picked by hand once the fruits have ripened. Green is under ripe, yellow is acceptable on parts of the fruit whereas ripe fruits are deep red. Purple is becoming over‐ripe and black is not suitable for pulping and is sundried as mbuni. Ripening is fast in hotter months and slower in the cooler months. In  cooler conditions a 10 ‐ 16 day round is common which is reduced to 7 – 10 days in hotter conditions. It is easy to determine the maximum time as coffee should be picked before becoming over ripe with a deep purple colour. Fruits then turn black and lose quality and are sundried.

Cherries do not ripen all at once, therefore the crop is picked about 7 ‐ 12 times throughout the season which makes the process very labour intensive. Younger coffee requires fewer harvests and older coffee flowers over a longer period resulting in an extended harvesting season.

Coffee is harvested into ‘kangaroo pouches’ made from hessian or plastic sacks and tied around the waist of the picker which allows the pickers to use both hands. It also facilitates picking from ladders on taller trees as both hands are needed for support. Ladders are made of light material and have three legs. The one is positioned under the tree and the upper part of this pole is used for holding onto as it extends upwards and outwards. The other two poles hold the rungs that are used for climbing. They are rigid but hinge onto the other leg for adjustment and ease of transport.

At the end of the season the remnants of the crop are stripped when it becomes uneconomic to continue harvesting and to assist in reduction incidence of pest and disease. All the ripe, green and overripe fruits are harvested and the crop usually sundried as unwashed coffee.

• PULPING TO DISPATCH

PULPING

Cherry is picked and taken for weighing at the field edge or directly to the pulpery. The term pulpery is preferred to the term factory. This is because a factory has industrial regulatory implications of processing.

The quality is checked on a canvas sheet or receiving tray before weighing. The green fruits, leaves, twigs, etc., are removed.

The cherry is then weighed for payment to the pickers, as it is usually carried out as task work. The amount that can be picked on average in a normal 8 hour day is used to pay the picker on a pro‐rata basis. Coffee is transported to the pulpery in an open trailer or in sacks on a trailer. Care must be taken to ensure that coffee that has been picked is not ‘recirculated’ for double payment. This is done by double checking all weights throughout the process

value chain.

At the pulpery the cherry is pulped by a pulper using dry feed or water. The pulper comprises a rotating disc or drum to remove the fleshy outer skin. The aquapulper uses water pressure to remove the mucilage as well. A number of makes and designs of pulper are on the market (e.g. McKinnon; Gordon, Pegasus). The coat of mucilage surrounding each  bean helps to lubricate the process and the tough inner parchment skin helps protect the bean from damage.

CHERRY PRE‐GRADER

A cherry pre‐grader can size the cherries if there is a wide spectrum in size (e.g. due to a mix of varieties). The discs can then be set according to the size of cherry that is fed to it from the pre‐ grader. The pre‐grader is normally of rotary design positioned above the pulper with different sized apertures to feed cherry to the preset discs.

SKIN SEPARATION (outer fleshy skin)

Most of the skins are separated from the cherry at pulping and disposed of separately to make compost.

SEPARATION OF FLOATERS AND HEAVIES

Water and pulping separates partially developed beans (floaters) from the well‐developed beans (heavies) which are fed to separate fermenting tanks.

FERMENTATION

Fermentation is either dry (with water drained out) or wet (under water) and takes from a minimum of 24 hours to a few days. Fermentation is the removal of the mucilage layer by microbial action. The beans turn from slimy and sticky to gritty when fermentation is and tested by rubbing a sample in ones hands. There is a trend to try and dry coffee without fermentation, ‘pulp natural’, and to sell into niche markets which are prepared to pay higher prices. However care must be taken to ensure no fruity taste occurs.

WASHING AND GRADING

Coffee (now wet parchment) is washed and graded after fermentation in grading channels, with weirs at regular intervals. It is pushed backwards with wooden squeegee (brush with no bristles)

against the flow of water in the channel. This agitates the beans and tends to allow the lighter beans and pieces of skin to flow over the weirs leaving the heavier ones behind.

DRYING WASHED COFFEE

After washing and grading into 3 grades (1st grade, 2nd grade and lights) the wet parchment is dried separately in the sun on drying tables, on concrete ‘barbecues’ or by artificial driers. It is important  to dry coffee slowly and uniformly. Initially the process is to get parchment skin dried as quickly as possible.

Parchment, when still white (30 ‐ 44% moisture), is dried at a depth of 25 cm thick on drying trays  (20 m2 of tray area is needed per tonne of cherry).

Once beans reach the black stage (30% moisture) the depth of beans can increase to 50 cm depth (10 m2 of tray area per tonne of cherry). The tables are covered with black plastic during periods of rain and at night to reduce re‐absorption of moisture.

The beans are dried uniformly over 7 ‐ 14 days until the parchment ‘rattles’ when rubbed gently between the hands. The outer parchment skin is removed by rubbing a hand full of beans continuously in the palm of both hands, working in opposite directions. This removes the  parchment. Use the thumb nail to see if the beans are hard. (The nail is not able to indent the bean but it leaves a ‘silvery’ mark). The moisture content is then within the range of 10.5 ‐ 11.5%. This is the most acceptable moisture content for delivery. If the bean indents, it is still too wet. If the bean snaps apart when bitten between one’s front teeth it is too dry and tends to be a yellow/green colour with an irreversible loss in quality. Very rapid early drying tends to allow the parchment to come apart.

Beans should be blue grey and not black in colour at the thickest part (too wet still). It is important  to be able to do these simple tests even if there is a moisture meter available.

DRYING UNWASHED COFFEE

Sundried unwashed coffee comes off the tree to be dried and misses out on all the above processes (pulping, fermentation, grading by water). It is dried in the same way as parchment but is protected by the dried skin and parchment.

STORAGE AND CONDITIONING

As soon as the coffee is dry it is stored in bags or silos for conditioning for 6 ‐ 8 weeks before it is bagged for dispatch with a uniform moisture content within and between the beans. Conditioning is often in bags that need to be moved and turned. Ventilated silos and/or wooden boxes are preferred. It is important to ensure that temperatures in storage do not exceed 22oC and humidity remains between 50% and 70%.

Coffee must not be too dry or too wet otherwise quality will be lost. Coffee conditions in storage after drying and the moisture levels within and between the beans become more uniform over time. In dry areas, the coffee will continue to dry out and in cool areas with high humidity the coffee can pick up moisture. It is of importance to track moisture and turn coffee in bags regularly. Coffee in storage should be kept off concrete floors and away from walls. The equilibrium moisture content (no gain or loss in moisture) is about 65% relative humidity. Humidifiers can be used to keep coffee from drying out.

SORTING

Handpicking  and/or  use  of  colour  sorters  help  to  remove  mbuni  (beans  with  skin),  black   and

deformed beans (e.g. antestia damaged). Sorting is best done by passing coffee over a simple light conveyor belt travelling at 4 m per minute with 5 people on each side. It should use less than 1 kVa  of power. The top grades of coffee have very strict limits. Normal allowance for imperfections is 1 to 4% and varies with the various grades.

DISPATCH: PARCHMENT COFFEE – WASHED

Coffee is usually dispatched in parchment form. Cherry to dry parchment ratio by weight varies from

6.5 ‐ 7:1. Parchment is then hulled (loss of 20% by weight from removing parchment skin from the green bean), graded, (normally at least 4 main grades), sorted and then sold as green bean in the various grades (normally at least 7). The green bean is sold directly or through auction.

GRADING AND FINAL SORTING OF GREEN BEANS AFTER HULLING

The different grades are produced first by passing coffee over screens of different sizes starting with 7 mm then 6 mm and finally 5 mm. This will produce four separate sizes. There is substantial difference in the price between high grade quota coffee and lower grade non‐quota coffee. Hand picking is as important as size grading in ensuring that the correct standard for quota coffee is reached.

The full range of grades and terminology, initially used in Tanzania, are still relevant today:

AA	Heavy coffee with largest beans of normal shape;
ABC	Heavy coffee in descending order of size;
PB	Heavy coffee peaberry of single round bean (one seed in bean);
E	Elephant – large open beans;
AF	Medium density coffee of AA and A sizes;
TT	Medium density coffee of B size;
T	Coffee of all densities smaller than C plus coffee of medium density of size C:
F	Coffee of light density all sizes larger than T.

Coffee for export must be in 60 kg bags made of jute, sisal or polypropylene. New jute bags must be washed thoroughly to remove the oily taint.

Coffee can easily pick up taints and care must be taken at all stages of processing to avoid taints (e.g. oil, plant) and contamination.

There are procedures to follow with the export of coffee which must be strictly adhered to, from proper marking of the bags to the official documentation required.

DISPATCH: MBUNI – UNWASHED

This is sold as whole sundried cherry which is hulled and sold as unwashed coffee.

• MARKETING

Coffee is sold directly into the market through commodity associations, directly to buyers normally by tender, or through an auction.

On the world market, the price of coffee is controlled by the supply and demand for the crop. The world’s largest coffee producer is Brazil and factors such as drought and frost in that country have a major influence on the supply and prices on the world markets. The graph below shows how a serious frost in Brazil in 1975 produced a world record price for coffee in 1977.

Figure 1: Impact of 1975 frost in Brazil on the prices in 1977

(Source: The Farmer 22/9/80)

Figure 2: Coffee prices (ICO) from 1998 to 2009 show volatility of supply and demand on the market price

The raw beans are bought by private companies which roast, grind and market the coffee, either in the form of coffee grounds or as powder or granules, known as instant coffee. The major roasting organisations are in Europe and the U.S.A., and the amount of raw coffee held in stock by them is another factor which affects the world price of coffee beans.

The actual world consumption of coffee increased as a result of the large scale promotion of coffee drinking. This came about because the U.S.A., a major consumer, dropped from 3.12 cups per person per day in 1962 to 1.92 cups in 1981. Consumption worldwide over the last decade has increased at approximately 2% per annum.