Kenya's vegetable crops invaded by soil pests

Lire en français Two soil-dwelling, invasive fly species are causing widespread devastation on vegetable crops in Kenya, due to lack of effective control options for smallholder farmers. A

study conducted by scientists from Kenya’s University of Nairobi and the International Centre of Insect Physiology and Ecology (ICIPE) showed the severe consequences of inadequate control

options and limited knowledge among smallholder farmers. Crop pests and diseases emerge as major threats to vegetable production analysed in the five counties (Nyandarua, Nakuru, Kiambu,

Kajiado, and Nyeri), highlighting the urgent need for efficient, cost-effective, and sustainable management strategies in Sub-Saharan Africa. The study, published in _Scientific Reports_

found _Delia platura_ as a potential pest in cabbage crops and _Atherigona orientalis_ in onions. In the fields affected by these pests, the severity of damage was high, with the researchers

detecting other soil-borne pests across different agro-ecological zones namely white grubs, wireworms, and sap beetles. Soil-dwelling pests that co-existed such as sap beetles and onion

maggots aided in the transmission of plant diseases, especially Fusarium basal rot, causing further yield losses, the researchers observed. While the occurrence, incidence and severity of

these pests varied considerably on cabbages and onions, the study says, more than 95% of the farmers’ application of synthetic insecticides had little success. “Climate change and habitat

destruction have led to high infestation of invasive crop pests that are very difficult to control. A considerable proportion of the devastating pests and diseases dwell in the soil and are

difficult to detect until irreversible damage has been done,” said Dennis Beesigamukama, the study’s co-author and post-doctoral research fellow in insect frass fertilizers and soil health

at ICIPE. The researchers call for the development of efficient, cost-effective and sustainable management strategies that target pests. “This will encourage a shift from synthetic

pesticides which are less effective, costly and harmful to humans and the environment,” Beesigamukama says.