The Effect of Entry into Dieldrin-Treated Soil Upon Adults of the European Chafer1

Abstract

Adults of the European chafer ( Amphimallon majalis (Raz.)) were introduced into cages which had been placed in untreated plots and plots treated with dieldrin granules at 2 pounds of actual toxic ant per acre. The bottoms of the cages were open, and the adults were free to burrow into the soil. Many more beetles were capable of emergence from untreated than from treated soils on the days following introduction. Application of the insecticide 10 weeks or 1 year before introduction of beetles caused fewer adults to emerge than application 5 days before introduction. Males were more susceptible than were females. Although the number of eggs laid in treated soil was reduced by more than 50%, no effect of the treatment upon egg viability was detected.