Effects of acephate (ortheneR) on development and survival of the salamander, Ambystoma gracile (Baird)

Abstract The effects of acephate, a water‐soluble organophosphorus insecticide, on the early growth and survival of the salamander, Ambystoma gracile, were examined. The 96‐h LC50 for 69‐day old larvae was 8816 mg/L. Exposure of egg masses to concentrations up to 798 mg/L did not produce significant differences in mortality up to the time of hatching. Larval mortality in the first 7 days after hatching increased at the higher acephate concentrations but declined in the period day 7–29 to low rates independent of acephate concentration. Growth rate decreased and morphological abnormalities increased in larvae exposed to 382 and 798 mg/L acephate. This component of lake fauna would be little affected by insect control programs which use acephate since maximum surface water concentrations would probably be < 1 mg/L.