CULTURAL MANAGEMENT OF RUSSIAN WHEAT APHID INFESTATION OF BREAD WHEAT VARIETIES IN KENYA

Wheat (Triticum aestivum L.) is ecologically suited to East African countries and is the second important cereal after maize in Kenya. It is an important source of food, livestock feeds and income. However, its production (442,000 MT) does not meet annual domestic demand (1,750,000 MT), due to cereal aphids infestation. The most serious cereal aphid in Kenya is the Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov), causing yield losses of 90% when not controlled. The objective of this study was to develop low cost cultural, sustainable and environmentally safe practices for the management of the RWA in East Africa. Treatments included nine varieties, three seeding rates and three rates of nitrogen application. Nine commercial wheat varieties, K. Tai, K. Kingbird, K Wren, K. Korongo, K. Hawk, K. Sunbird, Robin, K. Eagle, and NBWII were sown. Main plots were assigned to wheat varieties, sown at three seeding rates 75, 100 and 125 kg ha-1. Sub-plots were assigned to three rates of nitrogen, 75, 100 and 130 kg N ha-1, applied at tillering stage (GS 22). Variety K. Korongo supported the lowest aphid count of 3.6 per 5 plants; followed by K. Hawk (3.8) and Robin (2.9 aphids). Robin gave the highest grain yield (2.9 t ha-1), followed by K. Korongo (2.7 t ha-1) and K. Hawk (2.5 t ha-1). Application of 100 kg N ha-1 and seeding at 100 kg ha-1 were the best rates.