Effects of the Rice Root Aphid, Rhopalosiphum rufiabdominalis (Sasaki), on Wheat Growth and Yield

Abstract

The rice root aphid, Rhopalosiphum rufiabdominalis (Sasaki), has recently been identified on winter wheat (Triticum aestivum L.) in Oklahoma. This aphid is easily misidentified as the bird cherry-oat aphid (R. padi L.) and subsequent observations suggest it may be a more serious pest than previously believed. A survey of Oklahoma counties was done to expand the known distribution and field and laboratory experiments were conducted to determine the effects this potential pest species may have on wheat cultivars commonly grown in Oklahoma. The rice root aphid has been found on winter wheat across Oklahoma. Under ideal conditions, the rice root aphid had no impact on wheat seedling development and forage weights. In a field setting, a T-test revealed significant decreases in mean sample weights and mean seed weights. Also, during the fall of 2005, Oklahoma experienced drought conditions and the rice root aphid was observed at much higher infestation levels than ever before. It is possible that under drought-like conditions the rice root aphid will significantly affect forage and grain yields of winter wheat in Oklahoma.