The residual Toxicity of DDT to Bed-bugs (Cimex lectularius, L.)

Abstract

The investigations herein recorded show that DDT is more toxic to bed-bugs when available on a surface as an oil solution than as a dry film, and that the toxicity of the latter is determined to some extent by the volatility of the medium in which DDT is applied. The results of trials on filter paper, glass and unpainted wood suggest that the minimum period of exposure to a dry film of DDT necessary for the insect' to acquire a lethal dose is one hour, and that this critical period is constant irrespective of the nature of the DDT-treated material to which the insect is exposed. Tests with bugs on DDT-impregnated filter paper show that this period can be curtailed considerably by the addition of a fine oil spray.