A comparison of standardized methods for measuring the biological activity of pesticides to the earthworm, Lumbricus terrestris

Abstract

Standardized methods for determining LC and LD 50 values to the earthworm were compared. An LC 50 is most quickly determined by exposing the worms to an ethanolic dip for 30 min. LC 50 values can also be determined by soil-incorporation, a route which simulates natural exposure, although mortality sufficient for the estimation of an LC 50 is not generated until 7–14 days have elapsed. Injection into the hemocoel proved most efficacious for determining an LD 50 ; topical application was vitiated by irritation by the compound and the solvent. The symptoms which result from exposure are distinct and dose responsive. When using a standardized procedure for assessing toxicity, these symptoms are useful in gauging nonlethal effects of the compound and in facilitating comparison of data.