Some pests like the mealybug can kill an entire passionfruit vine if they multiply rapidly and take over the whole vine. Others, like aphids and nematodes are vectors for diseases, while others again damage the fruits and make them unfit for the market.
Mealybugs
Mealybugs (Planococcus kenyae) are small oval insects, covered in a white, waxy fluff. They attach themselves to the vines in protected places near the fruits, especially underneath the old, dried up flower bracts, and in the leaf axils. Mealybugs are also a common pest in citrus trees and pawpaws.
Different growth stages of the mealybug
Mealybugs suck sugar-rich sap (honeydew) from the plant. The sugar spreads over the surface of the plant and encourages the development and growth of sooty black mold. It is called sooty black mold because it looks as if the leaves and twigs of the plant are covered in black soot. As the sooty black mold grows and covers ever bigger areas, it slowly surpresses photosynthesis as the sunlight can no longer penetrate the mold to reach the leaves. The plant becomes week and might even die eventually. Sooty black mold is also caused by aphids and whiteflies, as they also suck honeydew from plants.
Sooty black mold caused by mealybugs
Mealybug Control
Mealybug control, same as all pest control, starts with good plantation management and regular scouting. Well-nourished plants kept under ideal conditions are much less prone to pest and disease attack than weak crops. Refer to the How to grow passionfruits blog for growing advice.
Mealybugs are best controlled when detected early. Scout especially just above the fruits underneath the dried up remains of the flower.At an early stage they can be squashed and whiped off by hand. They can also be washed off with a strong waterjet from a hosepipe. The water can mixed with a small amount of liquid dishwashing soap (1 Tablespoon per 5 liter).
For a stronger infestation you should still need to be careful not to use a pesticide that will also harm beneficial insects. One of the most powerful helpers in your plantation is a small black ladybug, called Cryptolaemus montrouzieri, with a bright orange head. This beetle and its larvae feed exclusively on mealybugs and will clean your plantation if left in peace to multiply without being disturbed. You need to be very careful to distinguish between the pest and the beneficial, as the larvae of the mealybug eating beetle almost looks like a mealybug itself. It can be found in the middle of mealybugs, on which it feeds and can be distinguished by its slightly bigger size.
Mealybugs are best controlled when detected early. Scout especially just above the fruits underneath the dried up remains of the flower.At an early stage they can be squashed and whiped off by hand. They can also be washed off with a strong waterjet from a hosepipe. The water can mixed with a small amount of liquid dishwashing soap (1 Tablespoon per 5 liter).
For a stronger infestation you should still need to be careful not to use a pesticide that will also harm beneficial insects. One of the most powerful helpers in your plantation is a small black ladybug, called Cryptolaemus montrouzieri, with a bright orange head. This beetle and its larvae feed exclusively on mealybugs and will clean your plantation if left in peace to multiply without being disturbed. You need to be very careful to distinguish between the pest and the beneficial, as the larvae of the mealybug eating beetle almost looks like a mealybug itself. It can be found in the middle of mealybugs, on which it feeds and can be distinguished by its slightly bigger size.
Larvae of the mealybug eating ladybug
The mealybug eating ladybug
Ladybug & larvae feeding on mealybugs
In the picture above the ladybug and its larvae are feeding on a clump of mealybugs. The larvae (on the top right of the white mass) can hardly be seen among the mealybugs. If you detect these ladybugs in your plantation you must not use any insecticides! This very valuable ladybug species was introduced into Kenya in the 1920s and was thought to be lost until its rediscovery in 1971. It must be protected by all means!
Organic pesticides
If neglect has lead to a strong infestation with mealybugs, which could kill entire vines, two organic pestice options are available. The first one is neem oil (or the less effective neem spray), which acts as a repellent and does not poison insects.
The other option is made from 1 garlic bulb, 1 small onion, and 1 teaspoon of chili powder (or any multiple of it). Process all ingredients together into a paste, either with a food processor or with a mortar and pestle. Mix the paste with 1 litre of water and let it steep for 1 hour. Strain through a cloth to remove any parts that could clog your sprayer and add 1 tablespoon of liquid dishwashing soap. Mix well. Spray on all infested areas. Repeat weekly if necessary. Only if infestation can not be controlled within a month you should consider using chemical pesticides.
The other option is made from 1 garlic bulb, 1 small onion, and 1 teaspoon of chili powder (or any multiple of it). Process all ingredients together into a paste, either with a food processor or with a mortar and pestle. Mix the paste with 1 litre of water and let it steep for 1 hour. Strain through a cloth to remove any parts that could clog your sprayer and add 1 tablespoon of liquid dishwashing soap. Mix well. Spray on all infested areas. Repeat weekly if necessary. Only if infestation can not be controlled within a month you should consider using chemical pesticides.
Sucking Bugs
A number of sucking bugs cause damage to the vines, growing tips and most importantly the fruits, rendering them unmarketable.
Marks on passionfruit left by sucking bug
 The puncture left by the sucking bug got infected with rot and enlarged, deforming the fruit also on the inside. |  |
Two kinds of sucking bugs are common in East Africa, namely Leptoglossus membranaceus and Anaplocnemis curvipes, which can both easily be identified by their peculiar, enlarged hindlegs.
Sucking Bug (Anaplocnemis curvipes)
They are also best controlled with preventive neem oil applications, which will repell any sucking insects.
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