Experiments on the possible use of Bacillus thuringiensis thuringiensis berliner in the control of crop pests. II. Susceptibility of some lepidopterous pests to B. thuringiensis

Abstract

Two commercial preparations of Bacillus thuringiensis thuringiensis Berl. were used in laboratory tests on two noctuids:Prodenia litura (F.) and Plusia orichalcea (F.); two pyralids, Leucinodesorbonalis Guen. and Chilo partellus (Swinh.); and one papilionid,Papilio demoleus L. On the basis of the results obtained it was evident that all the larval stages of Papilio were highly susceptible to both bacterial preparations, while Prodenia showed moderate susceptibility. The larvae of Plusia, Leucinodes and Chilo showed less susceptibility to one of the bacterial preparations tested. The results suggest that Papilio demoleus, a serious pest of young citrus in nurseries in India, may be efficiently controlled through spray applications of B. thuringiensis. The larvae of P. demoleus exhibited a fairly rapid paralysis followed by an increase of blood alkalinity after ingestion of spores, whereas P. litura larvae did not show any sign of paralysis or appreciable change in the pH of the haemolymph.