Control of Thrips and Aphids on Carnations with Systemic Insecticides

In tests against thrips, Frankliniella sp., with granular formulations at 5 Ib of the active ingredient per acre, dimethoate was the most effective of the materials tested. In one experiment in which there was a very heavy infestation, flowers cut from the dimethoate plots 1 month after treatment averaged 75.3% saleable compared with 16.1, 14.7, 5.7, and 0.7% for phorate, Di-Syston® (O,O-diethyl S-[2-ethylthio)ethyl] phosphorodithioate), phosphamidon, and the check, respectively. Dimethoate was also effective as a soil drench and as a foliage spray. In one experiment in which the plants were grown in heavy soil and watered at approximately 2-week intervals, granular formulations of dimethoate, phorate, Di-Syston, and phosphamidon at 5 Ib of the active ingredient per acre all failed to give satisfactory control of the green peach aphid, Myzus persicae (Sulzer.). When the experiment was repeated and the plants watered 4 times at 3–4 day intervals, all the materials except phosphamidon gave excellent control. Dimethoate was also effective as a soil drench but phosphamidon was not.