Contarinia baeri is univoltine in Michigan. Adults emerge in spring, and females deposit eggs in small clusters in the sheaths of new-growth pine needles. Larvae hatch shortly thereafter and there are three larval instars. Larval feeding causes the needles to at first droop, discolor, and eventually drop, reducing the quality of Christmas trees and occasionally killing shoots. Larvae overwinter on the ground in cocoons, and pupate in spring. Adults were suppressed (> 75% control) with formulations of Pydrin® (fenvalerate) and Tempo® (cyfluthrin) applied within a week after adult emergence.
Wilson, Louis F.; Sapio, Frank J.; and Simmons, Gary A.
"Biology, Injury, and Control of the European Needle-bending Midge (Diptera: Cecidomyiidae) on Scotch Pine in Michigan,"
The Great Lakes Entomologist, vol 21
Available at: https://scholar.valpo.edu/tgle/vol21/iss3/1