Cabbage Caterpillars: Efficacy of Chlordimeform and Bacillus thuringiensis in Spray Mixtures and Comparative Efficacy of Several Chemical and B. thuringiensis formulations123

Abstract

At least 1/16 lb/acre each of chlordimeform hydrochloride and Bacillus thuringiensis Berliner in a spray were needed for effective protection to cabbage against the cabbage looper, Trichoplusia ni (Hübner), the imported cabbageworm, Pieris rapae (L.), and the diamondback moth, Plutella xylostella (L.). Emulsifiable concentrate formulations of chlordimeform gave better plant protection and tended to give a greater reduction of the cabbage looper population than did a soluble powder formulation of chlordimeform hydrochloride. The addition of foam to the B. thuringiensis spray did not increase plant protection and injured the foliage. A liquid formulation of B. thuringiensis gave more effective plant protection than a wettable powder formulation even though looper populations were generally higher on plots treated with the liquid formulation. Neither formulation was as effective as Dipel® (Bacillus thuringiensis var. alesti Berliner) in reducing plant damage. Acephate and Monitor^® (O S dimethyl phosphoramidothioate) provided more effective plant protection than did the other compounds.