Effects of Metopolophium dirhodum on Spring Wheat in the Glasshouse

SUMMARY Pot‐grown plants of spring wheat, cultivar Maris Dove, Were subjected, commencing at ear emergence, to different, constant levelsof infestation hy Metopolophium dirhodum (Wlk.) in a glasshouse. Infestation with six aphids per stem over 11 days had no significant effect on yield. Infestations with either six or 50 adult aphids or their equivalents, when maintained until ripening, resulted in lower yields of both grain and straw dry matter. Loss of grain was due to reduction in both 1,000 grain weight and the average number of grains per fiertile spikelet. Harvested dry matter content of leaf blades was unaffected by infestation, but the dry matter, content of stems was reduced in infested plants. In breeding aphid‐resistant cereals for Britain, resistance characters restricting aphid multiplication are most likely to reduce yield losses due to aphid attack.