Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 1995
Publication Date: N/A
Interpretive Summary: The Russian wheat aphid is a serious pest of wheat, barley, and cool-season grasses. Plant introductions of tall wheatgrass were evaluated for resistance to the Russian wheat aphid, with several of the plant introductions identified as resistant. The most resistant plant introduction entry (PI 401010) was not damaged from aphid feeding, sustained low aphid populations, and the leaves did not curl. When the aphids were given free choice, the resistant plant introduction PI 401010 was the least preferred over the more susceptible plant introductions and susceptible wheat. The resistant plant introductions can be used in developing improved resistant forage grasses.
Technical Abstract: The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a recently introduced insect pest that is a serious threat to wheat, Triticum aestivum L., and barley, Hordeum vulgare L., production. Tall wheatgrass, Agropyron elongatum (Host) P. Beauv., not unlike other wheatgrass species, serves an important alternative summer host of the aphid and provides a bridge between spring harvest and fall planting of cereal crops such as wheat and barley. Experiments were carried out in the greenhouse to identify Russian wheat aphid resistant Plant Introductions (PIs) obtained from the Western Regional Plant Introduction Station, USDA-ARS, Pullman, WA. One PI (PI 401010) was identified to resist plant damage, leaf curling, and aphid reproduction. Additional experiments were carried out in the greenhouse to characterize the plant components (i.e., antibiosis, antixenosis [nonpreference], and tolerance) contributing to resistance of PI 401010 originally collected in Turkey. PI 401010 was compared with PI 401118, a Russian wheat aphid susceptible PI and tall wheatgrass cv. 'Alkar' and 'Jose'. PI 401010 showed high levels of antibiosis, demonstrated by delay in reproductive maturity, shorter reproductive lifespan, and reduced rates of nymph production compared to the other genotypes when infested with Russian wheat aphids although plant height was reduced by aphid feeding, and dry mass foliage loss per unit of aphid mass produced was relatively high. A strong antixenosis (nonpreference) resistance component existed in PI 401010 when aphids were given a free choice of several genotypes. PI 401010 is a valuable now source of resistance for germplasm enhancement efforts.