Sunflower Midge: Appearance, Territory, Damage and Life Cycle

Latin Name: Contarinia Schulzi

Appearance: The mature sunflower midge is just about a tenth of an inch (2-3 mm) long, with a brown body and clear wings. Eggs are yellow to orange in color and are placed in bunches on flower buds or occasionally on adult sunflower heads. The larvae are comparable in size to adults, are legless, and are yellowish-orange or cream in color. The lifetime of a sunflower midge begins when the adults’ lay eggs on the bracts (modified leaves) that enclose the flower buds. The larvae begin eating their way from the periphery of the budding sunflower to the center as soon as the eggs hatch. The larvae then fall to the ground and create cocoons a few inches (5 to 10 cm) underground.

Cocoons spend the winter beneath the earth, while adults emerge during the month of July. The adults find sunflower buds, deposit their eggs, then die a few days later. A second generation can emerge in late summer, perhaps inflicting more harm to mature sunflower heads. This generation’s adults lay eggs from mid-August to mid-September.

Hosts Plants: Sunflower, ragweed, and cocklebur are examples of host plants. The sunflower midge may be found on wild sunflowers from the northern Great Plains all the way down to Texas.

Territory: Contarinia Schulzi, the sunflower midge, is found throughout North America’s Great Plains, from Manitoba to Texas.

Damage Insect Cause: Look for brown scar tissue on the bracts, which are the little green leaves right below the sunflower head, to indicate sunflower midge injury. Seeds and part of the yellow petals on the margin of the head may also be lacking. If the infestation is severe, the head may become twisted and malformed, or the bud may never fully mature. The damage frequently emerges on the field’s margins. Adults are difficult to discover, although larvae may be visible if you cut open a damaged sunflower at the right moment.

Life History and Habits: Adults spend the winter under the soil and emerge in June and July in North Dakota, Minnesota, and Manitoba. Adults only survive for a few days and are difficult to find in the field. The adults deposit their eggs in the bracts, and the larvae feed on the borders of the head before migrating to the center as the head develops. The larvae develop and fall to the ground, where they spend the winter. In August, there is a second generation.