Observations on the efficiency of the so called "butter-trap" in trapping the German cockroach, Blattella germanica Linne

Abstract

For the purpose of estimating the population size, or of evaluating the effect of control operation against domiciliary cockroaches, the so called "butter-trap" has been generally used in Japan. Glass bottles, plastic pots and jars, etc., are generally used as trap, in which some bait is laid and a small amount of butter is thinly smeared inside the trap. The cockroaches attracted to the bait set in the trap are captured by it, being unable to climb up the butter-smeared wall. As the current method seems too insufficient for standard method, the attempt was made to increase the efficiency of the trap. Our experiment was conducted using German cockroaches liberated in a large metal case under laboratory condition. Fifty samples of various baits were compared in 24 combinations of a unit of 4 samples. Rice bran, barn-yard millet and a kind of commercial poisonous bait relatively attracted more cockroaches than the others. Rice bran may be most suitable for trap bait, because of their attractiveness, availability and cheapness. Cylindrical glass pot of 9cm in diameter and 6cm in depth caught most cockroaches amongst 4 trap vesseles tested. Margarine smeared inside the trap was superior to vaseline. The trap covered outside with sugar-impregnated filter paper gave best catch.