Use of low cost pest exclusion nets can boost cabbage yield

ABSTRACT In this study, low-cost pest exclusion nets (lcPENs) were evaluated to determine their efficacy in reducing pest infestation and enhancing yields of cabbage at KALRO Kabete and PTC (Practical Training Centre) Thika, Kenya, from March to September 2011 both at nursery and field production levels. Nets of two-mesh sizes (0.9 mm and 0.4 mm) were used whereby the 0.9 mm net was either impregnated or not impregnated with alpha cypermethrin to enhance efficacy through repellency effects of the pesticides. The lcPENs efficiency was compared with no-net use and grass shading (farmer practice) in a completely randomized block design with five replications. Results showed that diamondback moth (Plutella xylostella) larval infestation was lower (P<0.05) on cabbages covered with lcPENs both at nursery and field level. At nursery, aphids were lower (P<0.05) on seedlings covered with insecticide-impregnated lcPEN but in field conditions, there was no difference among the lcPENs. Cabbage yield was higher (P<0.05) on cabbages grown under lcPENs. The findings clearly demonstrate high incomes as a result of growing cabbages under lcPENs. However, there was no evidence of an increased role for insecticide impregnation except in the nets at nursery level. Hence farmers can use ordinary (un-impregnated) lcPENs for pest management in transplanted cabbage production.