Management of the Greenbug on Grain Sorghum. 1. Testing Foliar Treatments of Insecticides Against Greenbugs and Corn Leaf Aphids12

Abstract

Experiments were conducted from 1968 through 1970 to obtain information having specific application to the management of Schizaphis graminum (Rondani) on grain sorghum in the High Plains of Texas. Foliar treatments of insecticides were tested against the greenbug and the corn leaf aphid, Rhopalosiphum maidis (Fitch), with the following results: (1) many experimental and registered insecticides were effective against the greenbug, and several were effective against the corn leaf aphid; (2) the effective registered insecticides, considering both insecticidal and nonphytotoxic properties, were water-emulsion sprays of demeton, disulfoton, parathion, carbophenothion, diazinon, and malathion, and plant whorl treatments of granular disulfoton; (3) these compounds were tested at standard, commercially marketable application rates as well as at rates containing 2-10 times less toxicant. The reduced rates of most insecticides were equally as effective against greenbug as the standard rates. However, they were not highly effective against the corn leaf aphid; (4) the experiments did not demonstrate that the production of grain sorghum could be increased significantly by controlling the relatively light infestations of greenbugs encountered; and (5) there was no evidence to show that corn leaf aphids caused significant damage to grain sorghum in the experimental plots.