Bioassay of Derris extracts and its formulated products for insecticidal and mammalian toxicity

Thirty eight samples (formulations/extracts) were evaluated for phytotoxicity, toxicity and antifeedant effect against ten crop insect pests in the laboratory. These are diamondback moth, DBM (Plutella xylostella L.), cabbage moth (Crocidolomia binotalis L.), common cutworm (Spodoptera litura Fabr.), corn borer (Ostrinia furnacalis Guen.), cotton stainer (Dysdercus cingulatus Fabr.), okra leafhopper (Amrasca biguttula (Ishida)), peach aphid (Myzus persicae Sulzer), black bean aphid (Aphis craccivora Koch), corn seedling maggot (Atherigona oryzae Malloch), and bean pod borer (Muruca testulalis Geyer). Three derris crude water extracts (S3, S5, S6) were highly toxic to DBM and corn borer; and S6 was the most toxic to cabbage moth. Among the organic crude extracts, six (S4, S9, S13, S14, S15, S16) were highly toxic to DBM, cabbage moth and cotton stainer and four (S4, S9, S14, S15) to corn borer. S10, S11, and S12 were moderately toxic to these test insects. Of the eleven derris formulations, S44, S45, and S46 were highly toxic to aphids and S46 to DBM, cabbage moth and cotton stainer but moderately toxic to corn borer. One WP (S49) was toxic to DBM, cotton stainer and corn seedling maggot. S59 and S76 were highly toxic to the aphids and DBM; S76 was highly toxic to cabbage moth, and S59 to cotton stainer. Among the rotenone formulations bioassayed, S59 and S76 were the most toxic to the test insects except the cutworm and bean pod borer which are tolerant to all the samples. All the materials exhibited antifeedant effect. The various derris formulations were also evaluated for toxicity to fish and laboratory rats to determine their potential hazards to man and non-target organisms. Of the eleven formulations evaluated for fish toxicity, three were highly toxic to tilapia and five were moderately toxic by oral route but considered non-toxic dermally to laboratory rats. The rotenone WP's were moderately toxic to rats and can be classified as CAT 3 poisons and are recommended for further evaluations and development