Hessian fly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A gall midge (Mayetiola destructor) having larvae that damage wheat and other grain plants. It was believed to have been brought to North America by Hessian troops during the American Revolution.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun small fly whose larvae damage wheat and other grains