Toxicity of six Bacillus thuringiensis Cry proteins against the olive moth Prays oleae

The activity of six Bacillus thuringiensis (Berliner) Cry proteins against third-instar Prays oleae (Bernard) larvae was examined. Five of the toxins tested (Cry1Aa, Cry1Ab, Cry1Da, Cry1Ja and Cry2Aa) proved active against P. oleae, the highest larval percentage mortality being obtained with by Cry2Aa and Cry1Ja. LC50 values were 0.12, 1.2 and 6.17 µg/ml for Cry1Ca, Cry2Aa and Cry1Ja, respectively. Relative potencies were calculated and Cry1Ca was found to be significantly (44-fold) more toxic than Cry1Ja.