Japanagromyza viridula

The holey handiwork of the Oak Shothole Leafminer is appearing on its namesake hosts in southwest Ohio. The fly is also capable of damaging Chinese chestnuts. Populations appear to be higher this year than during the "outbreak" in 2019-2020.

The holey handiwork of the Oak Shothole Leafminer (Japanagromyza viridula, syn. Agromyza viridula) is appearing on its namesake hosts in southern Ohio. Similar damage may be seen on Chinese chestnuts (Castanea mollissima). The leafminer is a small fly belonging to the family Agromyzidae; the leafminer flies.

I received a phone call yesterday from Mark R. Apelt who asked whether or not the oak shothole leafminer fly (Japanagromyza viridula, syn. Agromyza viridula) could also infest chestnuts. It was an interesting question given that oaks and chestnuts belong to the same family, Fagaceae.

The oak shothole leafminer is a small fly belonging to the family Agromyzidae; the leaf miner flies. The leafminer produces four progressive symptoms: small pinprick-like holes, larger holes, dark brown "blotch mines," and ragged-looking leaves with missing pieces.

BYGLers are reporting that four unrelated springtime problems are causing some oaks in Ohio to look pretty ugly. None of these problems cause harm to the overall health of their oak hosts. However, singly or collectively, they certainly affect the tree's aesthetics.

What's making holes in newly expanding oak leaves in Ohio? The common name of the oak shothole leafminer (Japanagromyza viridula, syn. Agromyza viridula) clearly describes both the culprit and the damage they do to oaks. This small fly belongs to the family Agromyzidae; the leaf miner flies.