One of the most common causes of poor crop yield, especially in corn, is the prevalence of the European corn borer. This grass moth, along with other similar insects, arrived in the Northeast United States in the early 1900s. Named for its prevalence in corn crops, the European corn borer can also drastically affect the yield of peppers, soybean, cotton, apples and more. This problem was remedied in the late 1990s with the Bacillus thuringiensis (Bt) protein, which helped protect crops for a number of years. However, Bt is slowly losing its effectiveness against insects like the European corn borer, which has built up a resistance to the protein.
Identification
When in its larval stage, you can identify a European corn borer by its off-white colored body, dark-brown head and its smooth skin with dark round spots scattered across its body. The larvae can reach about one inch in length. As an adult moth, a borer can be identified by its yellow coloration and dark, “zigzag” markings across the wings. Identification and early treatment of infested crops is crucial because adult female moths can lay up to 500 eggs in their short lifespan. These eggs can hatch within a week’s time.
Detection
Borers are present in the early summer months. As the larvae feed, you’ll notice damage to leaves in the form of shot holes. These larvae will eventually move to the more protected area of the plant sheath where they will continue to feed, molt and grow. Larvae will occasionally bore directly into the ears where they feed on kernels, which can result in broken stalks and rotting of the plant.
Control Tactics
- Tillage. Till fields where borers were prevalent the previous year. Corn borers overwinter, so it’s important to disrupt their environment in the fall or in early spring before the adult borers emerge.
- Utilize a good weed control program. Adult borers hide in tall grasses and weeds during the day. A good herbicide will keep most of the moths out of fields. Also, be sure to keep field edges and fence rows clipped.
- Bt still does a great job controlling the borer population. Using transgenic corn hybrids that utilize Cry1Ab, Cry1F, Cry1Ac, Cry9c or Vip3A proteins can be very effective. Stine® Agrisure® Viptera brand corn ensures maximum yield by providing effective, season-long control over European corn borers and other harmful insects that can damage crops.
- Pheromone traps can help determine the flight period for moths. When captured, experts can estimate the potential infestation levels in the area and help predict when the larvae will emerge and begin feeding on plants.
- Many insecticides can be used for corn borer control. Granular formulations are recommended.
Stine has a number of –10, –11 and –20 hybrids in a wide range of maturities that are excellent options for controlling corn borer, some of which include Stine 9212-10, 9316-20, 9436-11, 9714-20, 9728E-20, 9808E-20 and 9814-20. To learn more about these hybrids, contact your local Stine sales representative.