Time response experiments with single dose and chronic treatment of dieldrin onTribolium castaneum.

After a single spray of dieldrin at different concentrations, insects die over a period of about 5 weeks, mostly in the first 3 weeks. The concentration of dieldrin in the insects decreases before the decline in mortality. After chronic poisoning some of the population tolerated the poison (at various concentration levels) and stayed alive. This final stage was reached after several weeks. For comparison, tests were also conducted with lindane, parathion and dichlofenthion. All produced an initial increase in mortality but subsequently the proportion of dead insects remained fairly constant up to 7 weeks.