Evaluation of Treatment Schedule for Several Insect Pests on Fruit and Vegetables with Methyl Iodide Fumigation.

The mortality effects of 2 hours exposure to methyl iodide (MI) at 10 or 15 o C were examined using seven species of insect pests associated with fruit and vegetables. As the result of fumigation at 15 o C, the larval stage of Frankliniella intonsa showed less susceptibility within two species of thrips. A dose of 9.3 mg/l was required to obtain 100% mortality. The 3rd nymph and adult female stages of Planococcus citri were more tolerant than its egg stage. 100% mortality was obtained at a dose of 29.4 mg/l. As the result of fumigation at 10 o C, Aphis craccivora was more tolerant than Myzus persicae. A dose of 7.7 mg/l was required to obtain 100% mortality. Tetranychus kanzawai and Tetranychus urticae showed similar susceptibility. 100% mortality was obtained at a dose of 13.9 mg/l. CT values were approximated by the results of the current study and prior survey, obtaining 100% mortality for each insect pest. The draft treatment schedules were then evaluated by insect pest group and commodity group. 2 hours fumigation was considered a feasible schedule for aphid, spider mite and thrips, and 3 hours fumigation was recommended for mealybug.