Insecticide and Growth Regulator Effects on the Leafminer, \u3ci\u3eLiriomyza Trifolii\u3c/i\u3e (Diptera: Agromyzidae), in Celery and Observations on Parasitism

The effects of different insecticides were compared on survival and development of the leafminer, L. trifolii, in celery in Michigan and parasitism was assessed in this non- resident population. Avermectin, thiocyclam, and cyromazine effectively controlled L. trifolii larvae or prevented successful emergence as adults. Moderate to high levels of resistance to permethrin and chlorpyrifos were present. Avermectin caused high mortality of all larval stages and no adults successfully emerged. Thiocyclam caused high mortality to all larval stages, but did not affect adult emergence from the surviving larvae. Cyromazine acted most strongly against early stage larvae before visible mines were present, caused little direct mortality of larger larvae, but prevented successful adult emergence. No parasitoids emerged from 2029 larvae collected and reared, in contrast to studies in sites where L. trifolii is a year-round resident