Maple Eyespot Gall Midge: Odd and Alien Like Tree Problems. (Part 2)

Thank you Nick Sanchez (District Forester – Kent, Montcalm & Ionia Counties) for your contribution to the “Odd and Alien LIke Tree Problem blog!

Maple Eyespot Gall Midge

Ever get the feeling you are being watched? Every May, a tiny, mosquito-like fly called an ocellate gall midge, Acericecis ocellaris, emerges from the soil to mate and lay eggs in the canopy of a maple, most often the red maple, Acer rubrum. When the eggs hatch, the larvae attach themselves to the underside of red maple leaves to feed. The leaf develops a ring of colors as a result of hormones injected by the midge larvae, forming the eye-like appearance of the insect gall. You can find peak maple eyespot colors in June. The nearly translucent larvae can be found just beneath the raised, darkened center of the eyespot.

The ocellate gall midge is not a “pest” in the traditional sense. It does not contribute significant harm to the tree, and natural predators such as parasitoids help keep populations in check. There is no need for chemical warfare in the form of insecticides to control these creatures. Good cultural practices such as selecting and planting the appropriate tree for the right site will go a long way in keeping your trees healthy.

The ocellate gall midge is dependent on red maple to complete its life cycle, a specialist of sorts. Luckily for the midge, red maple trees are abundant in our forests and landscapes, and are in some cases overrepresented as a result of fire suppression and a lack of good forest management.

As a native insect, there’s no need for alarm on this one but keeping an eye on your trees is always a good idea. There are many resources out there to help you solve the next big mystery or even sound the alarm to call attention to the establishment of the next big invader (look-up Asian Longhorned Beetle). And the next time you think all eyes are on you, grab your magnifying glass, conjure your natural curiosity (which actually makes you cool) and stare right back!

Nicholas Sanchez, CCF – District Forester – Kent, Montcalm & Ionia Counties


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