Toxicity of Chemical and Microbial Insecticides to Pest and Beneficial Insects on Poled Tomatoes1

Abstract

Multiple applications of insecticides were made to poled tomatoes in three experiments conducted during 1961 and 1962. High dosages of Bacillus thuringiensis var. thuringiensis Berliner showed promise for the control of the cabbage looper, Trichoplusia ni (Hübner), and the beet armyworm, Spodoptera exigua (Hübner), as well as for the prevention of fruit damage by the tomato fruitworm, Heliothis zea (Boddie). As expected, B. thuringiensis did not adequately control the potato aphid, Macrosiphum euphorbiae (Thomas), the western flower thrips, Frankliniella occidentalis (Pergande), or dipterous leafminers, Liriomyza spp. In one experiment, a reduction in the rate of parasitization of leafminer larvae by two hymenopterous species occurred in B. thuringiensis plots. Sevin^® (1-naphthyl N-methylcarbamate) as a dust, and DDT, diazinon, naled and Zectran^® (4-dimethylamino-3,5-xylyl methylcarbamate) as sprays provided good control of leafminers, cabbage loopers, and beet armyworms in one of the experiments. Each of these materials also greatly reduced the numbers of adult hymenopterous parasites in the experimental plots. Varying degrees of fair to excellent protection of fruit from tomato fruitworm damage was obtained with these compounds as well as with malathion, toxaphene, and DDT plus toxaphene.