Russian Wheat Aphid (Homoptera: Aphididae) Affects Yield and Quality of Wheat

Abstract

The effect of Russian wheat aphid, Diuraphis noxia (Mordvilko), feeding on yield and quality of winter wheat, Triticum aestivum L., was studied in the greenhouse and field. Cages were used to contain the aphids and to exclude natural enemies. Greenhouse experiments showed that plant height, shoot weight, and number of spikes were significantly reduced by Russian wheat aphid feeding through the jointing stage. Yield per plant was significantly reduced by infestation through the heading stage. In 1987-1988 and in 1988-1989, field study yields were significantly reduced by fall and spring periods of infestation. Yield was significantly affected by fall and spring infestations in 1987-1988 but not in 1988-1989. The economic injury levels for the spring infestations of 1988 and 1989 were 0.9 and 2.4 aphids per seven plants, respectively; those for the fall period of infestation were higher at 2.2 and 4.0, respectively. Tested only following the spring period of infestation, both protein content and mixing time of the resulting flour were reduced by the Russian wheat aphid. However, mixing time was still within the acceptable range (1.5-3.0 min) for bread-making.