Static bioassays were conducted to determine the relative acute toxicites of some insecticides, herbicides, fungicides, and a defoliant to the scud Gammarus lacustris.

Acute and long-term (20-day) toxicities of 40 insecticides to four species of freshwater malacostracan crustaceans (the scud, crayfish, glass shrimp, and aquatic sowbug) were determined in static and intermittent-flow bioassays. An extremely wide range in toxicity was found with scuds generally being the most sensitive, followed in descending order by glass shrimp, sowbugs, and crayfish.