Role of a hymenopteran parasite and a bacterium in the regulation of a lepidopteran pest in tropical ecosystem

Abstract

Occurrence of mortality due to bacterial infection by a gram negative bacterium and the hymenopteran entomophagous parasite Apanteles glomeratus (L.) was observed in a natural population of Catopsilia crocale Cramer, a defoliator of the ornamental and medicinal plant Cassia alata. On regular field observation during the seasons 1980–1981 and 1981–1982, it was found that mortality due to these factors was mostly confined to the Final larval instar and the pupa of C. crocale. A direct correlation was obtained between population density of C. crocale and the number of larvae'pupae killed due to these factors. As the incidence of the hymenopteran parasite and bacteria fluctuate along with the C. crocale population, consideration of the foregoing factors as potential biological control agents for the pest population of C. crocale, is suggested.

Résumé

Occurance de mortalite produite par infection bacterielle a cause d'une bacterie negative et le parasite hymenopteran entomophagous Apanteles glomeratus a ete observe dans une population naturelle de Catopsilia crocale Cramer. Un defoliataur d'une plante ornamentale et medicinale le Cassia alata. Dans les champs d'observation ordinaires pendant les periodes de 1980–1981 et 1981–1982, on a trouvé que la mortalite, due a ces facteurs se limite souvent a le'tape larvaire et de chrysalide. Une relation directe est obtenue entre la densite de la population du C. crocale et le nombre de larves tuees a cause de ces facteurs. Comme la frequence du hymenopteran et de la bacterie varie en proportion avec la population du C. crocale, nous suggerons de prendre en compte les facteurs ci-dexus comme agents biologiques potentiels dans le controle de la population du parasite C. crocale.