Abstract
A nuisance chironomid midge, Polypedilum nubifer breeding in eel culture ponds was controlled successfully with temephos but recovered or alternate species appeared within 1 month. Procladius sp. was tolerable to temephos and rather increased following the treatment. The species composition of zooplankton population in the ponds changed. The decrease of crustaceans and predatory rotifers by the insecticide seemed to cause the increase in other rotifers. Phytoplankton did not show a marked change soon after the treatment but increased its standing crop approximately 1 month after. No appreciable change occurred in the water quality by the application of insecticide.
