Tag Archives: allium leaf miner

Social Media, the Allium Leaf Miner, the PA Department of Agriculture and Me

Last week I was scrolling through Facebook and noticed a post by Northeastern IPM (Integrative Pest Management) Center. In it, they described a new invasive insect named the allium leaf miner (Phytomyza gymnostoma). While this insect is common in Europe, it has now been detected for the first time in the Western hemisphere, with Lancaster county PA being the first reported case. Since this initial identification, the allium leaf miner has also been discovered in Lehigh, Chester, Dauphin and Delaware counties.

I though that this was interesting but I didn’t give it too much thought.

Three days later I was working in the garden and noticed that the onion plants looked strange. The leaves were wavy and they felt like they were wilted. Since we’ve been having so much rain I knew that they weren’t dry but I pulled one up to see if there was a problem with the roots. Maybe all of this rain had caused some kind of root rot.

Onions with Allium Leaf Miner Damage

Onions with Allium Leaf Miner Damage

When I pulled up an onion, it was clear that it had a healthy set of roots and there was no evident of root maggots. But I noticed that there were marks on the leaves and when I pulled the leaves apart and looked into the stem, there were a number of small maggots tunneling through it. Then I remembered the Facebook post and realized that this looked like the allium leaf miner and it was now in Lebanon county.

I pulled up all of the onions and used a few to take pictures. I didn’t want this pest to spread so I put the onions into the garbage instead of the compost bin.

Later, as I thought about it, I realized that I should let someone know about my discovery. If this new invasive insect was in another county, the authorities needed to know this. So I sent an email with pictures attached to the entomologist at Cooperative Extension and he instantly forwarded my email to the PA Department of Agriculture. I heard back from the gentleman there quickly; he thanked me for the pictures and asked some additional questions.

When you’re a gardener and an amateur entomologist, it’s exciting to be a part of the early stages of discovery of a new invasive insect. But there was one thing that I should have done that I didn’t think of at the time. Pictures are nice but for a confirmed identification, the Department of Agriculture needs a sample of the insect. I should have saved a few of the plants and delivered them to the local extension office for testing. Oops!

When I go out to the garden again, I’m going to see if the chives or garlic are showing signs of this insect. If they are, I’ll certainly be collecting samples. Also, in my next post, I’ll be describing this new (to the Western hemisphere) insect.

But for now, I’m just grateful for social media and the information it provided me about the allium leaf miner. I’m also happy to help provide information to those tracking this new insect pest.