Abstract
Residual effect of dieldrin, lindane, chlordane, diazinon and DDVP to female German cockroach, Blattella germanica L., was estimated by contact with the residues of 50cc of 5% xylene solution per square meter for 2 minutes, 1 hour, 6 hours or 24 hours. The knockdown percentage was counted 6 days after the contact. The most effective insecticide was dieldrin, and the effectiveness descended in the following order : lindane, diazinon, chlordane, DDVP. For an example, the effective period after an-hour-contact to the residues was as follows : dieldrin, 29 weeks; lindane, 3-6 weeks; diazinon, 3 weeks; chlordane, 1 week; DDVP, less than a day.
