Variations in Damage to Wheat Caused by Russian Wheat Aphid (Homoptera: Aphididae) in Texas

Abstract

The Russian wheat aphid, Diuraphis noxia (Mordvilko), was discovered in Texas on wheat, Triticum aestivum L., in 1986, and 17 collections from 11 Texas counties were made that same year. Two Russian wheat aphid collections, designated as the Randall 2290 colony and the Swisher colony, were tested on four wheat varieties with three infestation levels to differentiate susceptible and resistant plants. Two aphids per plant were the best initial infestation level because higher levels caused too much damage and masked differences between the wheat varieties. Plant height, expressed as a percentage of an uninfested check, was a nonsubjective measure of plant response to Russian wheat aphid. In a second test, all 17 collections were tested on TX78V2290-36-1(TXGH2290) and ‘TAM 107’ with an initial infestation level of two aphids per plant. The results from the second test indicated that there were significant variations in damage between aphid cultures, and differences between colonies occurred within counties and between counties. Reproductive capacity of Russian wheat aphid was affected by variety and was highest overall on TXGH2290. We suggest that TXGH2290 could be used as a susceptible standard in future host plant resistant studies, and this breeding line has been recommended for release. These findings indicate that there are important genetic differences within Russian wheat aphid.