Comparative toxicity of abamectin, cyromazine and spinosad against the leaf-miner fly, Liriomyza sativae (Dip.: Agromyzidae)

The leaf-miner fly، Liriomyza sativae (Blanchard)، is one of the major insect pests of vegetable crops in Iran and other countries. To determine the toxicity (LC50) of bioinsecticides abamectin 1. 8% EC، cyromazine 75% WP and spinosad 24% SC against L. sativae، bioassay was done on its larval and adult stages under 25 ± 1°C، 65 ± 5% R. H. and a photoperiod of 16:8 (L: D). The LC50 values found to be 1. 5، 1. 8، 14. 3 ppm for abamectin، 34. 8، 38. 4، 1295 ppm for cyromazine and 4. 4، 12. 1، 13. 7 ppm for spinosad against the first and last larval stages as well as the adults of L. sativae، respectively. The toxicity of the insecticides on the larval stages was higher than on adults. Using a mixture of petroleum oil، as a synergist، and the insecticides significantly increased the mortality of the first instar larvae. The results indicated that cyromazine is ineffective for the control of adults، while it is proved to be effective against the leaf-miner''s larval stages. It is found that abamectin and spinosad are more efficient insecticides than cyromazine for the control of all developmental and adult stages of L. sativae.