Grain and Biomass Yield Reduction by the Russian Wheat Aphid on Bread Wheat in Northern Ethiopia

Russian wheat aphid (Diuraphis noxia Mordvilko) is an important insect pest of wheat and barley in Northern Ethiopia. We present loss data due to D. noxia on wheat from an experiment conducted at Mekelle Agricultural Research Center in the off season with irrigation. Insecticide (Fenitrothion 50 EC and Dimethoate 40 EC) treated and untreated plots were compared for biomass and grain yield, damage, days to heading and maturity. Significant differences were found in all parameters. Control plots also sustained significant leaf chlorosis and rolling damages. D. noxia reduced wheat grain yield 67 to 68% and biomass by 44 to 55%. Weight per 1000 seeds was reduced by 20%. Heading and maturity was delayed. Fenitrothion 50 EC, a contact insecticide, controlled D. noxia and prevented 67% reduction in grain yield and 44% reduction in biomass yield. This yield loss data highlights the need to develop sustainable D. noxia management that would safeguard irrigated and spring season wheat crop. Keywords: D. noxia, yield loss, whea