Hass avocado farming; pests and diseases affecting avocados in Kenya


Over years, Kenya has been one of the leading avocado exporters with most farmers earning a decent living from this ago-enterprise. The most preferred type is Hass avocado, preferred over Fuerte avocado, primarily because Hass sells at higher prices. Hass also takes fewer years to mature. Another advantage of Hass avocado is because it has two harvest seasons in a year. Hass avocados are preferred by most consumers and grocers because of their better taste and longer shelf life. Avocado can generally grow well in all parts of the country except for the coastal areas due to salinity. Ideal conditions for production of hass avocado,

• Temperatures

The tree requires cool to warm temperatures, with the minimum not falling below 70 degrees Celsius and a maximum of 200 C (the optimum range is 150c to 250c).

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• Rainfall

The rain should be an average of 1000-1600 mm a year and spread well throughout the year. Watering is crucial where rainfall is insufficient. Too much moisture promotes pests and diseases that tend to do well in wet conditions.

• The soil

In order for Hass avocado to flourish, the soil must be well drained and rich in minerals. The best soils are sand or alluvial loams, where the PH levels could be acidic or alkaline.

• Sunshine

Hass avocado trees do well outdoors where there is plenty of sunshine.

• Attitude

In Kenya, the most ideal height above sea level for avocado production is 2500m.

Cultivation Procedure Of Hass Avocado

• Preparation of the land

The land must be tilled before planting commences. There must be availability of well decomposed manure and water back-up. If there is strong wind, make sure that the necessary wind breakers such as hedges are put in place.

• Planting holes

Tree spacing of 17ft × 17ft is preferred with an acre carrying an estimation of 150 seedlings. The spacing distance depends on various factors, such as soil fertility and climatic conditions. Also keep in mind that avocados have an extensive root system and can disturb the roots of other plants if planted too close.

The holes must be 60 cm by 2ft. It is advisable to plant the trees in straight lines to enable the management and harvesting of crops.

• Planting

Planting must be done after the rain starts when the rain water has penetrated the ground in the right way. In each planting hole you separate the upper soil and the other soil, then combine the upper soil with 20 kg of well rotten manure, remove the seed plant from the pot, keeping the basis and the soil structure intact and plant the seedling using the top soil mixture. If possible, plant it in a place protected from wind and frost, taking into account a lot of sunlight.

• Watering

If you plant avocado trees during the dry season, there is always the risk of sun damage because they do not absorb water properly when they are young. Water newly planted trees immediately, then two to three times in a week.

However, the frequency must be reduced during the rainy season. The uniformity of the fruits is strongly influenced by the frequency of their irrigation, as noted in an article by Daily Nation of Saturday, November 4, 2017 by Leopold Obi. .

• Pruning

Pruning is done to maintain the shape and height of the tree and to remove broken parts of the tree. It is mainly done during the flowering and after completion of the harvest. Pruning improves yield and ensures a superior tree


• Thinning

Thinning means that some of the already formed fruit is removed in order to reduce the competition for nutrients, and thus guarantee high-quality fruit.

• Fertilizer application

Fertilizer application is aimed at adding the necessary nutrients to the fruits. Not all farms need this and some require different types of fertilizer. Some factors that determine the amount and type of fertilizer used include the growth phase, the climate, the characteristics of the soil fertility and the yield of fruit.

• Control of pests and diseases

It is worth noting that grafting greatly improves fruit resistance to diseases. Always look out for fungal problems such as white mildew in humid climates. Other preventive control measures include weed control, correct selection of plant material, maintenance of optimal plant density and proper fertilizer application.

• Weed control

Weed control reduce competition for nutrients and water. Weed control is also seen as a means to control diseases and pests. Some of the strategies

for weed management include mechanical cultivation, cover cropping and mulching.

• Harvesting

As mentioned earlier, Kenya Hass avocado has two harvest seasons per year, one from March to July and the other from September to February. The harvesting of the fruits is done manually.

Avocados ripen on the tree and are normally harvested raw and ripen afterwards. The harvested fruits must be stored at a warm temperature to ripen evenly.

Most are ripe and ready to eat after a day or two.

Pests and diseases affecting the hass avocado


• Mites: Mites cause brown spots on leaves and fruits. They increase the leaf falls. They establish a web dates which appears as a silvery spot. Good farming procedures, including proper pruning and irrigation, are necessary to maintain their control. Note that insecticides are responsible for their expansion of these insects population. The use of horticultural oil is a recommended measure.

• Insects Borers: They tunnel into avocado trees, where they lay eggs. This causes branches to weaken and fall of. A preferred measure to prevent their spread is to cut out the infected branches immediately.

• Lace-bugs: Causing yellow spots on leaves, lace bugs result in damage of leaves. When the weakened leaves fall out, the fruits and the wood are exposed to ultraviolet rays which are very destructive. Horticultural oils or pyrethrin are recommended for their treatment.

• Thrips: these causes leathery scars on fruits. They can be eliminated with pyrethrin. Organic mulch is also recommended to discourage the survival of these insects.

• Caterpillars: Caterpillars spread damage to fruit, flowers and leaves. Sprays of Bacillus thuringiensis are very effective; giving special attention to the folded leaves where the caterpillars tend to thrive.


A. Fungal diseases

• Avocado root rot: This is reported to be the most common and most serious disease, causing pale, wilted leaves and very small fruits. The disease, which is caused by the fungal pathogen Phytophthora cinnamomi,normally thrives in moist, poorly drained areas. Some measures such as hot water treatment of seeds and grafting can help prevent this.

• Scab: This disease is caused by Sphaceloma perseae fungus and attacks fruits, twigs and leaves. The symptoms are oval or irregular spots on the fruits. Poor drainage causes growth and spread. It is controlled with the use of copper-containing fungicides.

• Anthracnose: Caused by pathogen Colletotrichum gloeosporioides, this affects the fruits, flowers and leaves, leaving dark spots and defoliation. Prevention of this disease involves pruning the dead branches of the affected tree before fungi produce spores and maintaining the correct conditions for the harvested fruits. It is controlled using copper-based fungicides.

• Avocado black streak: This tree infection causes black streaks on the bark. This disease can be well prevented by adhering to proper fertilization and irrigation practices.

Cercospora fruit spot: Fungi

Pseudocercospora purpurea also affects the fruits, leaving small, light yellow spots that eventually turn brown on leaves and fruit. This disease mainly occurs with poor sanitation. It is controlled using copper-based fungicides.

B. Viral diseases

• Algal leaf stain: Caused by the virus Cephaleurors virescens, this disease affects the trees so that red spots are visible on the leaves, twigs and branches. Preventive measures include correct weeding and pruning. Serious cases can be treated with copper-based fungicides.

• Sunblotch:

Virus Avocado sunblotch viroid, this is a much more serious condition of the trees and once contracted, it cannot be cured. It causes stunted growth, discoloration of fruits and the leaves and reduced yields. Prevention of this disease can be maintained through proper sanitation. In addition, since this disease can be transmitted via grafting, one must ensure that they purchase certified seedlings.

C. Bacterial diseases

Bacterial soft rot: This causes a dark, stinking rot on the fruit. Once contracted, the disease cannot be cured. For this reason, it must always be a necessity to buy seeds that have been certified and maintain a high level of sanitation in all agricultural procedures. Hass avocado farming has a promising future and it is for this reason that many farmers in different parts of the country embrace it. Cultivation of Hass avocado is a journey that requires a lot of patience as it takes at least 2 years for the trees to mature and bear fruit. The results of this patience are undeniable owing to the growing demand and shooting prices of Hass avocado worldwide. The lifetime of Hass avocado tree is more than 50 years. Apparently in an article published by Vitalis Kimutai on April of this year, Beliot Langat, a Hass avocado cultivator in Bomet County, reported that he started the business with only Sh 20 fifteen years ago and over time he gets nearly Sh 300,000 per season.


  1. I’m a prospective avocado farmer and want to start right from the word go. Please attach me to marketing companies for assistance.


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