The Control of Aphids, Which Infest Cauliflower. Seed Beds on Long Island, By Means of Tobacco Dust Mixtures

Abstract

Of late years the cauliflower growing industry on Long Island has been seriously endangered owing to lack of healthy plants in the seed bed. This condition is largely due to injury caused by aphids, Myzus persicae Sulz. and Macrosiphum solanifolii Ashm., which migrate from the vast areas of potatoes onto the seedlings. There the migrants breed rapidly under favorable weather conditions. Several insecticides have given satisfactory results in killing aphids, notably nicotine sulphate solutions, soap solutions, nicotine sulphate dusts, but each method has under practical conditions failed to give satisfactory control. The chief reasons for this failure are faulty means of application and excessive number of applications that are required to meet incessant infestation, which entails excessive labor costs. Tobacco dust-hydrated lime mixtures have shown effective killing properties and have given efficient control when applied to the seedlings. The advantages of this method of treatment are, (1) cheapness and simplicity of application, namely by hands, (2) the limited number of applications necessary (weather permitting), namely two or three. The disadvantage to the method is the necessity for heavy applications of the mixture, which entails a higher cost of material than in the case of nicotine sulphate sprays or dusts. Tobacco dust mixed with hydrated lime in equal proportions by weight has resulted in as efficient control as less diluted mixtures. The tobacco dust as used in the experiments was of 200 mesh fineness and of 1% nicotine content.