Neem seed extract spray applications as low-cost inputs for management of the flower thrips in the cowpea crop

In field trials conducted at the Experiment Station and in a farmer’s field at Mbita near the shores of Lake Victoria, Kenya, applications of 2% or 3% neem seed extract (NSE) @ 200 l/ha with a knapsack sprayer at 38, 47 and 51 days after emergence (DE) of the cowpea crop or 5%, 10% or 20% NSE sprayed @ 10 l/ha with an ultra-low-volume applicator at 31, 39 and 49 DE often significantly reduced the number of larvae of the flower thrips,Megalumthrips sjostedti (Trybom), in cowpea flowers recorded 2 days after each treatment. Also fewer adults occurred in flowers at 51 DE in plots sprayed with 5%, 10% or 20% NSE. Cowpea grain yield was significantly higher in plots sprayed with 20% NSE than in untreated control plots and was comparable to the grain yield obtained in plots sprayed thrice with cypermethrin. Because of the low cost of NSE treatment, the net gain was often more when the crop was sprayed with NSE than with cypermethin. Also, grain quality was superior in neem-treated plots than in untreated or cypermethrin-treated plots.