The Allium leafminer (ALM) is an invasive insect that was first reported in NYS in spring 2017. ALM specifically attacks allium species; most notably leeks, shallots, garlic, chives and dry bulb onions. There are two generations of this pest. The first flight occurs in the spring when overwintered pupae emerge from the soil. The insect then undergoes an aestivation period during the summer and re-emerges in the fall.
The best way to scout for presence of this insect is to inspect the distal ends of the allium spp. leaves for the characteristic oviposition marks, as displayed in the images above. The female makes these puncture marks with her ovipositor to both deposit eggs in the leaf tissue and produce leaf exudates which the adults feed from.
Our lab is working on developing integrated pest management strategies to control this pest and thereby preserve the integrity of NYS’ onion production system.