Effects of the insect growth regulator pyriproxyfen in a two-generation test with Chironomus riparius

Pyriproxyfen a juvenile hormone analoga (JHA) was used in a two-generation test with Chironomus riparius (Diptera). The protocol is an extension of the OECD test methods to test duration from first-instar larvae in the parental (P) generation to emergence of midges in the filial (F1) generation. Test species were exposed to concentrations ranging from 0.001 to 0.1mg/L. The results showed significant adverse effects compared to the solvent control for emergence rate (p<0.001), development rate (p<0.001), fecundity (p<0.05) and fertility of egg ropes but not for the sex ratio. No observed effect concentrations (NOEC), respectively, lowest observed effect concentration (LOEC) values were lower for emergence rate and development rate in the F1 (0.003mg/L, respectively, 0.01mg/L each) than in the P generation (0.01mg/L, respectively, 0.03mg/L). The two-generation test provided additional information, which might be useful in the risk assessment of agrochemicals with potential endocrine effects.