Noxia Resistance Research Articles

Plant Resistance Studies with Diuraphis noxia (Homoptera: Aphididae), a New United States Wheat Pest

Diuraphis noxia Mordvilko, a new United States aphid pest of small grains, was detected in the southern Great Plains in 1986. Our research objective was to obtain information about potential hosts and sources of resistance to this new pest in United States cereals and forage grasses and to determine whether greenbug-resistant germ plasm would be useful in a plant resistance program. When components of resistance of 10 small-grain seedling entries were compared, highest levels of antibiosis, antixenosis, and tolerance to D. noxia were found in ‘Nora’ oats, followed by ‘Elbon’ rye. In a replicated flat test comparing seedling reactions of 20 small-grain entries, greatest levels of resistance were again found in oat and rye entries, with moderate levels found in the wheat entries ‘Payne’, CI 17959, and CI 17882. However, it appears that current greenbug-resistant wheat and barley lines do not have sufficient D. noxia resistance to be useful in a plant resistance program. A test of other cereal grains and grasses showed that corn, sorghum, pearl millet, ‘Kentucky 31’ fescue, and bermudagrass sustained little damage, whereas Kentucky bluegrass and perennial ryegrass were moderately damaged. Some reproduction was observed on sorghum, but not on corn. D. noxia can be reared on pearl millet for short durations.