Allium Leafminer Gets Growers’ Attention

PITTSBORO, N.C. — This spring some growers in the North Carolina piedmont have noticed unusual problems with their allium crops, primarily bulb onions, leeks, and garlic. Obvious above-ground symptoms include twisted/distorted leaves, stunted plants, and even plant death. Below ground, brown pupae can be found infesting the plants and upon close inspection larvae can be seen feeding inside the leaves and bulbs.

It turns out the culprit is allium leafminer (ALM) which is a new pest in North Carolina. The allium leafminer fly (Phytomyza gymnostoma) is an invasive insect pest from Europe that was first detected in the northeastern U.S. in 2015 and has now spread to a few other states. It was first detected in North Carolina last year.

I have visited a few area farms to collect samples and take photos. I have also been busy reading up on this pest and talking with specialists at Cornell University about their experience with ALM over the past eight years.

I created a new web page with photos and lots of information that I will keep updated as we learn more about the allium leafminer here in North Carolina. This tiny little fly unfortunately has caused serious problems especially for organic growers in the northeast so we will need to take it seriously!