Control of the Green Peach Aphid on Tobacco with Systemic Insecticides1

Abstract

During 1960 several systemic insecticides were tested for their efficiency in control of the green peach aphid, Myzus persicae (Sulzer), which attacks tobacco grown in Maryland. Preliminary studies were conducted in the greenhouse to compare the relative effectiveness and rates of disappearance of several systemic insecticides, both as granulated materials applied to the soil and as emulsions applied topically to the foliage. Dimethoate and phosphamidon emulsions resulted in a high level of mortality to confined aphids until the end of the test, a month after the insecticides were applied. Ph orate granules applied at the rate of 4 pounds per acre to soil in the pots caused a high rate of mortality until the end of the experiment. Soil applications of phosphamidon granules were ineffective. During the growing season of 1960 field experiments were conducted to evaluate a number of systemic insecticides, their rate of application, the time of application and the methods of application. Phorate and Amer. Cyan. 18133 ( O,O -diethyl O-2 -pyrazinyl phosphororthioate) were effective when applied as granules sidedressed at the normal time tobacco is side-dressed with fertilizer. Phosphamidon and dimethoate were both effective when applied at 0.25 or 0.5 lb. per acre. Late applications, made after aphid populations were well established, were more effective than early applications.