Tomato farmers using black threads in supporting the plants off the ground can cut on pest control unlike those using yellow threads, which attract multiple crop enemies.
Most farmers pay little attention to the material provided it serves the purpose.
Supporting every plant with one or two yellow strings turns the greenhouse or open field coloured, therefore, attractive to the pests. This means that they would spend more on controlling the pests
The commonest insects attracted by yellow fruit piercing moths, aphids, whiteflies, leafhoppers, thrips, leaf miners, among others.
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Amiran Kenya Agronomist Timothy Munywoki said insects are easily identified by light receptors and that is why the colour is used in integrated pest management systems traps.
“Insects will land on the strings and then move to the plant. No amount of chemical application can wipe out the pests because they keep coming back as long as the attraction points are there. This is worse in open fields where the yellow strings turn the area coloured, therefore, susceptible,” he said.
Besides eating into the profits of the farmer, more losses accumulate, application of more pesticides increases diseases risks resulting from the chemical residues.
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As an integrated pest management practice, Amiran Kenya has a yellow sticky gel that is pasted on polythene sheets. Hundreds of aphids, whiteflies, beetles, among others are found dead daily.
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While beetles drill into the fruits, reducing their quality, heavy infestation of whiteflies and aphids causes shrinking of the leaves. Reduced leaves translate to little food being synthesised for the tomatoes. Leaf miners extract the juice from the leaves, making the plant weak and susceptible to stress.
PHOTO: Kisii University farm manager Peter Ondieki inspects tomatoes at the institution’s demonstration farm at the Kisii Agricultural Society of Kenya Show Ground on July 15, 2016. Yellow strings in staking attracts insects to attack tomatoes. Amiran Kenya Agronomist Timothy Munywoki says black is the recommended colour. PHOTO BY LABAN ROBERT.