The Occurrence of Cereal Aphids in Rainfed Wheat in Kenya: The Problem and Possible Integrated Pest Management Strategies

Abstract

Cereal aphids cause direct damage to rainfed wheat through sucking of plants sap and cause losses of up to 90%, particularly in dry years in Kenya. The Russian wheat aphid (RWA) is the most destructive and may account for up to 50% yield loss or more depend‐ing on the severity and length of infestation. Current control strategies mainly rely on the use of insecticides to control cereal aphids’ infestations. Chemicals improve yields in the short term, but adversely affect the environment, hence the need for development of effective IPM strategies. Early planted crops escape heavy aphid attacks and give good yields. A combination of seed rate of 100 kg and 100 kg N/ha provided the best cultural management of RWA. Ladybird beetles Adonia variegata, lacewings (Chrysoppaspp.) and parasitic wasp Aphidius sp. were the most important natural enemies. Control of cereal aphids can be achieved with systemic insecticides applied as seed dressings or foliar applied insecticides. Four lines of wheat were found to show RWA resistance and crosses with Kenyan wheat made and populations are being evaluated for resistance to cereal aphids.Keywords: wheat, cereal aphids, natural enemies, cultural strategies, insecticides, host plant resistance1. IntroductionGrain cereals contribute significantly to food security in Kenya. Bread wheat (Triticum aestivum L.) is the second most important cereal crop in Kenya, after maize. It was grown on 147,210 ha producing 328,637 tons of grain with a yield of 2232 kg/ha [13]. However, there © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,distribution, and reproduction in any medium, provided the original work is properly cited.