Predatory Midge Larvae In Corn

 

The Plant Diagnostic Clinic recently received a sample of corn stalks infested with bird cherry oat aphids, which were also harboring midge larvae. The larvae are closely related to and also resemble the gall midge larvae found in soybean. However, in this instance the larvae were found on the surface of the corn stalk in association with the bird cherry oat aphids. While some species of midges are pests (e.g., gall midges) there are also species that are considered beneficial. One predatory midge species in particular (Aphidoletes aphidimyza) is known to consume many different species of aphids. 

 

The beneficial midge larvae are very similar in appearance to the species that was found in soybean. They are small, and vary in color from white to bright red or orange (Figure 1). The adult flies are small, black, and are active at night. As adults, these flies feed on aphid honeydew and nectar. The key difference between the predatory midge larvae and gall midge larvae is their location on the plant. Gall midge larvae are found beneath the epidermis of the plant, or in gall formations present on the plant. The predatory midge larvae are always found in association with aphid colonies.