Allium Leaf Miner

Allium leaf miner (ALM) feeding/egglaying scars were detected in chives and scallions near Princeton (Mercer Co.), NJ on Friday of this week.  This indicates that the second (fall) flight of these flies is now underway, and damage is occurring.

Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion

Growers should consider initiating the control method of their choice at this time.  Affected crops include chives, scallions, garlic, onions and leeks.

Floating row covers, kept on until the second 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), and pyrethrin materials (Pyganic (OMRI approved)), neonicotinoids (Scorpion, Venom) and the insect growth regulator Trigard are labeled for miner control.

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 second adult generation.  We will attempt to identify the end of the second flight so that growers know when the risk of infestation has abated.

Allium Leaf Miner

Allium leaf miner (ALM) feeding was detected in one commercial planting of chives near Lawrenceville, NJ on Tuesday of this week.  Degree-day accumulations at this site were 46.5, base 50 F as of Tuesday.  Sticky traps at this same site yielded no flies.  Additionally, trap and inspection sites at Milford (Hunterdon Co. (garlic)), and Oldwick (Hunterdon Co. (garlic and chives)), had neither feeding signs nor flies on sticky cards.

Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion

Within the week, another monitoring site near Hackettstown (Warren Co.) will be added.    Reasonable spring weather that we are now experiencing is conducive to the development of the first adult generation.  Growers should consider initiating the control method of their choice at this time.  Affected crops include chives, scallions, garlic, onions and leeks.

Floating row covers, kept on until the first 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), and pyrethrin materials (Pyganic (OMRI approved)), neonicotinoids (Scorpion, Venom) and the insect growth regulator Trigard are labeled for miner control.

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 onset of 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.