Farmers can control aphids, white flies and mites in their farm by intercropping their crops with coriander (dhania) as the herb attracts the ladybird insect which feeds on the pests.
According to One Kind, a Scotland animal protection organisation, a ladybird can eat about 5,000 aphids during its three to six weeks lifespan.
One ladybird lays about 1000 eggs in clusters or rows on the underside of a leaf with a suitable prey such as aphids. After hatching, the insects start feeding immediately on the pests. The insect’s larval stage in the most active stage, where they actively feed, therefore, disarming the pests.
Presence of aphids is confirmed by black sooty mould on the affected crop.
Aphids and white flies feed on the crop from the underside of the leaves. This condition reduces the surface area for photosynthesis, the food making process in plants. Because of the extraction of the nutrient-rich sap, some leaves turn yellow due to malnourishment, which also reduces photosynthesis resulting from the absence of the green pigment.
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Edwin Atuya, a tomato and cabbage farmer for instance suffered 80 per cent losses on his eighth an acre farm three years ago due to invasion by aphids on his crops.
“After planting three rows of coriander in between my tomatoes I learnt through observation that the herb induces ladybirds which in turn feed on the aphids thereby reducing their population,” said Atuya.
“This in turn has saved me Sh1200 every season in pesticide costs,”
For effective control, coriander is planted earlier than the main crop as this ensures they ladybirds will be ready for action once the main crop is transplanted.
This biological control of pesticides will help farmers avoid rejection of their horticultural produce in the international markets.
In 2017 for instance, Kenya’s fresh produce (fruits, vegetables and flowers) to the European Union was rejected 29 times due to infestation by pests and produce having exceeded minimum pesticide limits of 10 per cent maximum residue level.
Coriander is used as an ingredient in food acting as a spice. It helps to reduce blood sugar, control blood pressure, reducing coughs and diarrheas.