The Hass avocado variety is the most popular Kenya avocado for export because it enjoys a good market in Europe as compared to the other varieties. Hass is originally from Guatemala and one of its most prominent features is that it turns dark purple when ripe. The fruit grants the following benefits which generally apply across the family of avocados;
1. They are high in protein and mineral content, compared to animal protein.
2. Avocados are an essential source of good cholesterol.
3. They are used in cosmetics, for example, in the manufacture of facial and hair oil.
4. Economically, they are a good source of income for farmers besides earning foreign currency for the country especially Hass avocados.
Avocado growing is largely a permanent investment and, therefore, there is need for careful planning before venturing into it. In Kenya, Hass avocado is mainly cultivated by both large-scale growers and small scale farmers.
Hass avocado does well in altitudes between 1000m to 2000m. The fruit is generally bigger in cool areas as compared to warm areas. The optimum temperature is 20 to 24 degrees celcius. Although avocados are fairly resistant to drought, well-distributed rainfall of between 1000-1200mm is adequate for proper crop development. They also require well-drained soils to avoid root rot. The best soils are sandy or alluvial loams with pH ranging from 5 to 7.
Avocados can be grown from seeds or from seedlings. Grafting improves the variety by increasing its resistance to diseases, improving yield and increasing its adaptability to different soils. The planting material should be inspected by relevant personnel to ensure they are free from diseases. Seeds should be treated with hot water not exceeding 50C.
This should be similar to the preparation of land for other crops. In case of newly cleared land, it is advisable to plant an annual crop a year before growing avocados, in order to achieve a good tillage of the cleared land. If there are strong winds, ensure the necessary wind-breakers such as hedges are in place.
It is advisable to plant the trees in straight lines to facilitate crop husbandry and harvesting. In Kenya, the rectangular pattern of planting is preferred for hass avocados, as it eases movement of machinery in between rows as well as other activities such as inspection, thinning, and pruning.
Tree spacing depends on several factors such as soil fertility and climatic conditions. Spacing may range from 6m by 7m to 8m by 10m.
The planting holes should be around 60 cm to 70 cm. Take soil samples when digging holes while taking care not to mix the topsoil with the subsoil. Collect 10 to 12 samples of the top soil at a depth of between 5cm to 15cm and repeat this process for subsoil at a depth of below 16 cm. Send the two samples to a legitimate soil testing center or to the National Agricultural Laboratories.
Use about two buckets of farmyard manure properly mixed with top soil, 250gm of double superphosphate fertilizer, and a certfied insecticide to fill the planting holes. Planting should be done after the onset of rains when rainwater has properly penetrated the soil. When filling up the holes, do not damage the roots. Irrigate the newly planted Hass avocado trees or seeds preferably until the first shoots appear. Tie the young plants to sticks to support them.
Pruning starts at the planting stage where roots that are too long and do not fit in the planting hole are reduced in size. During the early stages of growth, trees are trained in order to maintain a good framework. Pruning is also normally done before flowering and upon completion of harvesting. The general guideline is that the tree canopy height should be 70% of row width. This allows light to penetrate. Pruning improves yield and provides a superior tree structure.
This involves removing some of the already formed fruits in order reduce competition for nutrients, therefore ensuring high-quality fruits. Too many fruits will result to small sized fruits.
Weed control reduces competition for nutrients and water. Some of the methods for weed control are mechanical cultivation, cover cropping, and mulching.
Pests and Diseases
The most efficient and economical method of pest and disease control is prevention. These preventive measures include weed control, proper selection of planting material, maintaining optimum plant density and proper fertilizer application.
In Kenya, avocado production is not considerably affected by pests and rarely will pest control require a chemical application. However, some of the major pests attacking avocados include
1. False codling moth which is a brownish, night-flying moth.
3. Scale insects.
Fungal diseases may also affect avocados and therefore need to be checked. They include;
1. Root rot. Also known as Phytophthora cinnamomi, it is mostly found in areas with poorly drained soils and flood prone areas. Some of the preventive measures include fungal and hot water treatment of seeds and grafting on phytophthora resistant rootstock. There are two chemicals registered to combat this disease i.e. Ridomil, active ingredient Metalaxyl, is a granular formulation which is applied in the soil, and works by killing the pathogen. Aliette, the second chemical is applied onto the leaves.
2. Anthracnose. It’s also called Colletotrichum gloeosporioides. It attacks the fruits, forming dry, dark brown sports. It mostly attacks mature fruits. It is controlled using copper based fungicides as well as spraying with chemicals such as Benomyl, Mancozeb, Metiram, Propineb, Thiabendazole or Triforine.
3. Cercospora fruit spot or Pseudocercospora purpurea also affects the fruits leaving small, light yellow spots which eventually turn to a brownish color on leaves and fruits. It’s controlled using similar methods to Anthracnose.
4. Scab. It attacks fruits, twigs, and leaves. Lesions emerge as little dark spots a little raised and are oval or elongated. It’s controlled using similar methods to Anthracnose.
Kenya Hass Avocados flower at around October and are mature for picking between June to September. It is important to know how to identify the correct harvesting period because avocados are harvested raw and ripen off the tree. Harvest a few fruits and keep them in favourable conditions to ripen. If the fruits ripen evenly, they can be considered to have been mature. Careful picking of similar fruits from the trees can now commence.
The yield depends on several factors such as proper pest and disease control, plant density, and soil fertility among others. Generally, the average yield of Hass avocados in Kenya is 87 780 fruits per hactor.
There is great potential for Hass avocado production in Kenya, especially for export. Some regions especially the central region and the rift valley region have impressive climatic conditions for the production of this fruit. The biggest challenge, however, remains lack of understanding among some farmers on the pesticides minimum residual levels (MRL) guidelines by the European market. Without this crucial information, there is a danger of farmers producing fruits only for them to be rejected by the export companies. Every effort should be made to sensitise the farmers about these guidelines to ensure the highest export quality of Hass avocado is produced in Kenya.