The Seasonal Prevalence of Occurrence and the Life Tables of the Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae)

Abstract

The life table studies were carried out during two years from April 1982. Population density of Plutella in the area of Tokyo was high during spring and late autumn but remarkably low in summer and winter. This feature of population fluctuations could be explained with the analysis of ten life tables obtained throughout a year. Such seasonal fluctuations related with action of natural enemies. Rapid decrease of the density seen in summer was principally caused by the rise in mortality of the eggs by an egg parasitoid and predation by ants. Vast increase in spring was considered to cumulate individuals by prolongation of development during winter in every stage under the condition in the absence of natural enemies. © 1985, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.