Zu Fragen der Massenvermehrung und des Gesundheitszustandes der Gammaeule, Autographa gamma L. in der DDR im Spätsommer 1962 (Lepidoptera: Noctuidae).

Abstract

During the occurence of the Beet Worm (Autographa gamma L.) in the middle and southern parts of the German Democratic Republic there was investigated in late summer of 1962 the course of the outbreak (state of health, phenology of flight, natural mortality). The total of 5000 caterpillars and pupae from 32 localities were studied as to their percentage of healthy, sick, and parasitized specimens. In places with a high population density of the pest insect there was found a higher percentage of mortality, without regard of the food plant. There are given results on relations between the weight of pupae, date of emergence, and number of eggs. Bacterioses and polyedroses caused a high mortality of both the caterpillars and the pupae. 16 species of parasites were ascertained. Parasitization was low (2,0% by Tachinid flies, 0,3% by Ichneumon flies). Trichogramma evanescens Westw. successfully parasitized eggs of the Beet Worm in the field as like as under laboratory conditions. There are given notes on body measures of Tr. evanescens reared from the eggs of both the Angoumois Grain Moth (Sitotroga cerealella Olivier) and the Beet Worm.