Evaluation of Border Crops against Infestation and Damage of Cabbage by Diamondback Moth ( Plutella xylostella

Abstract

Hasheela, E.B.S., Nderitu, J.H., Olubayo, F.M., and Kasina, M. 2010. Evaluation of border crops against infestation and damage of cabbage by diamondback moth ( Plutella xylostella ). Tunisian Journal of Plant Protection 5: 99-105. Different trap crops were evaluated to determine th eir effectiveness in reducing diamondback moth (DBM) infestation on cabbage. Tomato, kale, Indian mustard, coriander, cleome and radish were planted around cabbage var. Copenhagen market plots to pull or push the DBM away from the cabbage. The field experiment was carried out in tw o relay cropping periods (September to December 2008 and January to March 2009) at University of Na irobi farm, Kenya. Border crops were planted 15 days prior to cabbage transplanting to facilitate c abbage protection around the whole plot, in a Randomized Complete Block Design with four replicat es. The counts of larvae, pupae and damage score were recorded weekly in situ on five randomly selected cabbage plants per plot from third week of cabbage transplanting for eight weeks. At maturi ty, cabbage heads were counted and weighed, then classified as marketable or unmarketable depending on the level of damage. Results showed that there was significantly ( P < 0.05) lower number of immature DBM in cabbage sur rounded with Indian mustard compared with other types of border crops. In addition, there was significant difference between marketable and unmarketable cabbage heads a mong the border crops, with Indian mustard and coriander bordered plots recording highest marketab le yield. These two border crops were more effective in reducing DBM infestation. Farmers are advised to incorporate these crops in the management of the pest in the field. By adopting th ese, farmers will be able to reduce pesticide spray s targeting this pest and also gain from these border crops through generation of extra income.