Abstract: A series of laboratory experiments were carried out to test the biological activities of Aver mectins against the vegetable leafminer Liriomyza sativae Blanchard. The results showed that the LC₅₀ of Jieyangmygin for the first, 2nd and 3rd instar larvae were 1.54 ×10^-4 g/L, 3.73×10^-4 g/L and 1.99×10^-3g/L, and that for Abamectin were 1.48×10^-4 g/L, 3.68×10^-4 g/L and 1.97×10^-3g/L, respestively. The first instar larvae of L. sativae was the most sensitive to Avermectins in the three instars, the LC₅₀ of Jieyangmygin against the 3rd instar larvae was 12.9 times that of the first instar larvae. For fe male adult, the LC₅₀ at 24 h, 48 h by residue bioassay to Jieyangmygin were 3.12×10^-3 g/L and 2.08×10^-3 g/L. Feeding and fecundity of adults were inhibited by Jieyangmygin for 4-8 d and 10 d, respestively. When the larva were exposed to the leaves which had been treated with 0.005 g/L Jieyangmygin, their survival rates within 6 d, 8 d and 10 d were 0, 16.13% and 28.07%, respectively. The results from field trials indicated that the population density of leafminer reduced by 91.1% and 90.9 % after treated with 0.005 g/L Jieyangmygin and 0.0045 g/L Abamectin in 6 d and there is not significantly different between them (P >0.05 DMRT). The results also showed that the population density of the leafminer reduced by 93.6% after treated with 0.0067 g/L Jieyangmygin in 6 d.

Key words: Liriomyza sativae Blanchard, Avermectins, Jieyangmygin