Evaluation of Insecticide Chemistries Against the Leek Moth (Lepidoptera: Acrolepiidae), a New Pest in North America

The leek moth, Acrolepiopsis assectella (Zeller), is a newly introduced micro-lepidopteran pest in North America that attacks Allium crops, including onion, leek, and garlic. Eggs are laid on leaves and emerging larvae may cause extensive damage by mining leaves, feeding on leaf surfaces and feeding directly on bulbs. Little is known about existing natural enemies for this pest in North America, but classical biological control introductions are underway in Canada. However, other management options are needed because the threat to the onion production industry in New York State and the Great Lakes Region is imminent. Laboratory studies showed that lambda cyhalothrin (Warrior® II), spinetoram (Radiant® SC), methomyl (Lannate® LV), chlorantraniliprole (Coragen®), and spinosad (Entrust®) significantly increased larval mortality, compared to the control, at 2, 4, and 8 days after treatment, while Bacillus thuringiensis and azadirachtin insecticides did not. These results are explained in part by the behavior of the insect.