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.
Basic control measures of keeping your hass avocado free from pest and diseases
- Planting the grafted species, (hass variety). Grafting greatly improves plant resistances to diseases.
- Weed control. Weeds are harmful in many ways. They harbour insect, pests and diseases:- Weeds either give shelter to various insects, pests and diseases or serve as alternate hosts.
- It helps to remove moisture reducing the chance of fungal infections and other air-borne diseases. The moisture is removed as the sun penetration will have increased when the fruit tree is pruned.
Pest affecting Hass avocados tree
They are a group of insects that lay their eggs on or inside of trees, where the young larvae eat their way through tissues.
Tree borer insects cause affected parts of trees to slowly weaken as their chewing severs vital transport tissues. Over time, they may girdle trees or weaken branches to the point that they break under pressure.
Thrips cause leathery scars on fruits. Organic mulch is recommended to discourage the survival of these pests. Pyrethrin can be used to eliminate thrips.
They damage fruit flower and leaves. Check on folded leaves as caterpillars tend to thrive there. They are eliminated by using a natural pesticide like pyrethrin or a systematic insecticide.
Diseases affecting Hass avocado trees
- Fungal diseases
Causative agent – Colletotrichum or Gloeosporium
Symptoms-Spots form on leaves, beginning as yellow, then brown discolorations that coalesce into large dead areas. Necrosis occurs across or between leaf veins, on leaf margins, and most often at leaf tips. Before harvest, brown to black lesions less than 0.2 inch (5 mm) in diameter develop around lenticels on infected fruit. These small discolorations can be overlooked while fruit are still on the tree, and lesions usually do not enlarge until fruit ripens after harvest. After harvest, lesions become blacker, larger, and increasingly sunken. Lesions eventually spread over the entire fruit surface and throughout pulp.
Remedy– removing all dead fruits, leaves and branches at the end of the year and cleaning up any debris or dropped fruits that might accumulate underneath. Prune your trees so the insides are more open and allow the wind to penetrate, reducing life-giving humidity in the canopy. Spraying the tree with copper fungicide every two weeks after blossom drop will ensure that your fruit is protected throughout its development.
Avocado root rot
Casuative agent– phytophthora cinnamomi.
Symptoms– light green to yellow, undersized foliage on infected plants. Leaves may also have brown, necrotic tips or margins.
Remedy-use certified disease free nursery stock, or use a systemic fungicide
Causative agent –sphaceloma perseae
Symptoms – lesions that appear are black and brown and scattered across the fruit skin.
Remedy – application of copper based fungicide when flower buds appear and 3 to 4 weeks later.
Symptoms – Yellow, pink, whitish, or red streaks and spotting of the bark and twigs and limbs.
Remedy – no treatment for sun blotch since it arrives with the plant.
Bacterial soft rot
Symptoms – Gray to black, mushy, foul smelling rot on fruit; fruit has darkened metallic sheen.
Remedy – no known treatment. Use certified seedlings while planting seedlings.