European corn borer
Ostrinia nubilalis (Hübner)
Adult is a pale yellowish brown moth with irregular darker bands running in wavy lines across wings; male is distinctly darker than the female (A). Larva is pale brown or pinkish gray with a black head and inconspicuously marked with small, round, brown spots (B).
Most fruit-growing states and provinces in eastern North America, south to northern FL.
Attacks apple mainly, and occasionally cherry and peach. Larvae feed on foliar terminals of young plantings (C) in early summer, causing leaves to turn brown and wilt, which can leave the tree disfigured. Partly grown larvae migrate from weed hosts and attack fruits later in the summer, tunneling through the flesh and creating galleries filled with frass (D).
Larvae may resemble those of oriental fruit moth (Grapholita molesta) or codling moth (Cydia pomonella), which may be distinguished from the former by the lack of an anal comb, and in both cases by coloration and the presence of raised brown tubercles on abdominal segments, which are more evident in later instars.
Infestations tend to occur under unusually hot and dry conditions, which affect normally preferred weed hosts in or around orchards, and also in orchards near woods. A good weed control program will reduce chances of orchard infestations. Pest's presence and flight activity can be monitored with pheromone traps. A selective insecticide such as Bacillus thuringiensis can be applied during late summer, when regular spray programs tend to be relaxed.
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.