Abstract
A limnephilid caddis larva, Nothopsyche ruficollis (Ulmer), was used for development of a new acute toxicity test. The larvae were put in a Petri dish with test solution at 20°C and under a continuous light condition for 48 hours. One-day-old larvae just after constructing their cases were more suitable for the test than larvae of later stages because larvae of uniform size were easily provided from egg masses and had relatively long life without food. Susceptibility of the larvae to 5 kinds of insecticide, 3 kinds of herbicide, 2 kinds of fungicide and 5 kinds of inorganic compound (heavy metals and a cyanide) was examined. The larvae showed high susceptibility to insecticides, but not to other chemicals examined, especially heavy metals.
