UNL Extension Entomologist Provides Expertise on Stalk Borers

Weed control can prevent future stock borer damage.
Weed control can prevent future stock borer damage.

As many Nebraska farmers know all too well, even a healthy corn crop can be impacted by stalk borers. These pests not only feed on corn, but more than 100 other species of plants, ranging from garden vegetables to soybeans. Now, entomologist Robert Wright of the University of Nebraska-Lincoln Extension is providing information on the stalk borer life cycle, its behavior, and how to reduce its damage to corn.

Female stalk borer moths often lay their eggs on grasses in the late summer and early fall. The eggs hatch in late April or early May, and the larvae tend to bore into stalks of grasses to begin feeding. Over time, they migrate to corn plants as others are mowed or burned down with herbicide. It is around this period that stalk borers begin to feed on corn.

Larvae are often brownish-purple and have three white stripes at the front and rear ends of their body. However, fully grown larvae do not have any notable markings. Farmers may begin to notice stalk borer larvae damage in May and June. The borers eventually tunnel into the stock, creating deformed or stunted plants.

Weed control can prevent future stock borer damage. Making management decisions based on predicted degree days can also give farmers the best chance of controlling the problem. Those who want to use insecticides must apply them before the stalk borer larvae enter the stalk. Insecticides can also be mixed with fast-acting herbicides to burn early-season weeds.

More information on stalk borer biology and management tactics can be found on the University of Nebraska-Lincoln Extension’s website at cropwatch.unl.edu.