Evaluating border cropping system for management of aphids (Hemiptera: Aphididae) infesting okra (Malvaceae) in Kenya.

A field experiment was carried out in 2003 and 2004 in Kenya to evaluate border-cropping system as a strategy for management of aphids infesting okra (Abelmoschus esculentus). Four crops used as border crops; maize (Zea mays), sorghum (Sorghum bicolor), pigeon peas (Cajanus cajan) and millet (Pennisetum glaucum) were planted 14 days prior to okra sowing, providing a protection perimeter around the whole plot. The number of live and parasitized aphids was monitored in situ on randomly selected leaves of okra in each plot for ten weeks. This was also done weekly on pods of randomly selected okra plants per plot for seven weeks after their formation. The number of aphids in okra leaves was significantly (p<0.05) different among the treatments during the two seasons. The plots bordered by pigeon peas and maize had lowest and highest mean aphid population among the border crops, respectively. However, maize bordered plots recorded the highest number of parasitized aphids in both seasons. In all the treatments, there was no significant difference (p>0.05) in the yield of okra. This study concludes that some border crops have potential use in aphid management in okra crop and can be used in combination with border spraying in an integrated pest management strategy to maintain the pest below economic damage. In addition, such a system would lower insecticide sprays in a season, reduce cost of production and improve farm profits. The strategy is also friendly to the environment.

African Dryland Institute for Sustainability , University of Nairobi