Aphid infestations (Homoptera: Aphididae) on spring oat (Avena sativa) cv. \u27Ogle\u27, and during the fall on winter wheat (Triticum aestivum) cv. \u27Clark\u27, composed mainly of Rhopalosiphum padi and Macrosiphum avenae, were reduced with applications at the 2-3 leaf stage of slow release granular formulations of acephate, carbofuran, and disulfoton, compared with carbofuran 15G and untreated controls, in field trials during 1990-1991 in northwestern Indiana. These field results corroborated those obtained by previous studies with the same formulations and dosages in the laboratory.
In oat, all insecticide treatments reduced aphid populations and percent- age aphid~infested plants, with a residual action of ca. 25 d. Barley yellow dwarf virus-like visual symptoms were reduced with disulfoton. In winter wheat, the residual action of all insecticide treatments in the fall lasted up to 19 d. The carbofuran treatment on winter wheat seedlings caused earthworms to move out of the soil, where they died; an effect requirining further study. Percentage of aphid-infested plants revealed relatively Wlder differences among tratments than total number of aphids in both test crops. Predation by Coleomegilla maculata (Coleoptera: Coccinellidae) contributed to the overall reduction of spring populations of cereal aphids in wheat and oat. Aphid mummies parasitized by micro-hymenopterans were common in oat plants
