Laboratory Studies on the Response of German Cockroaches (Dictyoptera: Blattellidae) to an Abamectin Gel Bait

The response of Gennan cockroaches, Blottello germonico (L.), to an abamectin gel bait (0.01% [AI] abamectin B1) was tested. In 5-d tests, mortality of large nymphs was ≥95% in no-choice and choice experiments (gel bait versus partially pulverized dog food pellets). Mortality varied with age and sex in populations (n = 2) of 80 cockroaches that were exposed continuously to the bait and dog food. Within 2 wk, the mean mortality of nymphal groups, adult males, and females bearing early-stage ootheca was 99.2, 85, and 45%, respectively. Hatch began on day 18 and mortality of newly hatched nymphs on day 22. By day 28, mortality of newly hatched nymphs and adult females was 98.5 and 90%, respectively. None of the cockroaches survived for >34 d. The control population consisted of 76 of the original 80 cockroaches and 276 early instars at the conclusion of the experiment (day 34).