Allium Leaf Miner
Allium leaf miner (ALM) adults were captured in higher numbers (16/week) on yellow cards in Princeton (Mercer Co.), NJ on Tuesday of this week, while lower numbers (2) were found near Milford, Hunterdon County. Additionally, a garlic field near Asbury on the Warren/Hunterdon border was found to have 64% of plants exhibiting feeding/egglaying scars. This indicates that the first (spring) flight of these flies is now in full swing, and damage is ongoing. ALM flies were observed on foliage in all fields that were inspected this week.
Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion
Growers should consider implementing the control method of their choice at this time. Affected crops include chives, scallions, garlic, onions and leeks.
Floating row covers, kept on until this flight ends will help minimize access to plants. Insecticide applications targeting adults may be helpful as well, although frequency of applications is uncertain. Spinosyn materials (Radiant, Entrust (OMRI approved)), pyrethroids (Mustang Maxx, Warrior), neonicotinoids (Scorpion, Venom) and the insect growth regulator Trigard are labeled for miner control. The diamide, Exirel, is permitted in NJ under a 2ee label as well.
Adult activity and observations of feeding will be reported on in the IPM Update as they occur. At this time, all growers should respond to the first adult generation. We will attempt to identify the end of the first flight so that growers know when the risk of infestation has abated.
