Growing cabbage (Brassica oleraceae var. capitata) under low cover Agronets prevents pest infestation and increases yields in Kenya

Abstract

Cabbage (Brassica oleracea var. capitata) is an important vegetable crop in Kenya both in production and income provision to smallholder farmers. Pests are serious hindrance to its production and most farmers rely on synthetic insecticides. Such reliance has negative effects on non-target organisms, environment, animal and human health. This study was carried out from May to October 2011 to determine impact of low cover nets of different mesh size and cover duration on reducing cabbage pest infestation and yields. The study was conducted at Kenya Agricultural Research Institute Kabete and Practical Training Centre Thika based on a randomized complete block design with five replicates. Treatments included Agronets of fine (0.4mm) and large (0.9mm) mesh covered over the crop permanently (season-long) or temporarily (opened three times a week from 9am to 3pm) and control where no Agronet was used. The results show that the number and damage by diamondback moth (DBM) was significantly lower on cabbages grown under the Agronets compared with control. Infestation by thrips was lower on cabbages grown under permanent cover compared with those under temporal cover and without cover. However, there was no significant difference of aphids infestation. The marketable yield was significantly higher on cabbages grown under the Agronets, recording about 17% yield loss compared with control that recorded about 90% yield loss. The study concludes that Agronets provide an important component of integrated pest management strategy for cabbage production in Kenya with high crop yields benefit and highly recommended for application by growers. Key words: Agronet, Aphids, Cabbage, Diamondback moth, Thrips