Plantwise Factsheets for Farmers
Neem extracts against whiteflies in beans
Recognize the problem
are tiny white winged insects of about 2mm. They usually sit on the underside
of leaves. They fly off when you shake the beans. Young whiteflies are also white and sit
underneath leaves, but do not move much. Young and adult flies feed plant sap
which causes yellow spots on bean leaves, and weakens the plants. They
release a sugary liquid which covers the leaves when there are many flies. A
grey-dark mould then grows on top.
are mainly found in warm weather. Bean plants usually tolerate a few
whiteflies per leaf but if there are many, then often chemicals are sprayed
which are toxic to you and the environment. Insects do not like some wild
plants, like the neem tree. Neem trees can be used to prepare homemade or
even commercial insecticides. Leaves can be used but the anti-insect
ingredient is most concentrated in the seeds. Neem is an insecticide, insect
repellent and anti-feedant. It is used against a wide range of pests such as
mites, cutworms, jassids, grasshoppers and also whiteflies.
is a fast growing tree which is wide spread in Zambia. It grows well on poor
soils and shallow or stony ground, and requires little rainfall. Neem seeds
or neem products can also be bought in agro-input dealer shops. The tree
bears fruit when about 4-5years old.
ripe golden neem fruits from the tree.
level of anti-insect substances is higher in ripe fruits compared to young
the flesh around the seeds and dry the seeds in the sun to avoid rotting
about ½ a handful of dry neem seed (25 to 50g). Shell and finely grate or grind.
powder into a piece of cloth and place it in 1 litre (about 4 cups) of water
to soak overnight.
a 16 litre knapsack sprayer you would need 6 to 8 handfuls of ground neem
seed (800g) to soak in 16 litres of water.
1 tablespoon (10mls) of liquid soap or chopped bar soap into 1 litre of spray
solution, or about ½ a cup (120 to 150 mls) into 16 litres of spray solution.
soap spreads the sprayed solutions over plants and insects.
early morning or late evening when the flies are inactive.
- Avoid using neem too often as they can destroy
useful predators and can be phytotoxic to the crop
The recommendations in this factsheet are relevant to:
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