No abstract

An outbreak of the serpentine leafminer, Liriomyza trifolii (BURGESS) occurred on many ornamental crops and vegetables in the spring of 1990 in Shizuoka Prefecture, Japan. The fly proved impossible for growers to control with conventional insecticides. Insecticides were evaluated for control of the fly on a bean (Phaseolus vulgaris L.) in the laboratory.Among 54 insecticides tested by spraying on one-day-old larvae, isoxathion, thiocyclam, cartap, cyromazine, and flufenoxuron gave high mortality.The LC50 values three days after treatment were 33, 72, 236, 4.8, and 103ppm, respectively. Eight days after treatment, the LC50 values for the insect growth regulators (IGRs), cyromazine and flufenoxuron, were 3.0 and 2.8ppm, respectively. The granular systemic insecticides cartap and acephate gave good larval control. High pupal mortalities occurred with the prepupae were placed on a polyethylene film treated with isoxathion, cyromazine, cartap, and thiocyclam. Isoxathion, thiocyclam, and ethofenprox had high adulticidal activity and reduced the number of feeding and oviposition punctures. Cyromazine and flufenoxuron lacked adulticidal activity and the repellent effect on feeding and oviposition. However, adult females exposed for 2 days to the IGR-treated foliage had reduced eggs and larvae viability. Adult females that survived the IGR treatment as larvae had fewer progeny.