Scouting for caterpillars in Pennsylvania corn

By Blake Jackson

As silage harvest continues in Pennsylvania, farmers are scouting their fields to assess crop progress and identify any potential pests. One of the most common pests found in corn ears is caterpillars.

In Pennsylvania, there are four main types of caterpillars that can damage corn ears: corn earworm, fall armyworm, western bean cutworm, and European corn borer. Each of these species has a unique appearance and feeding behavior.

Corn earworms are the most common type of caterpillar found in corn ears. They are typically brown or green in color with stripes down their bodies. Corn earworms enter the ear through the silk and feed on the kernels.

Fall armyworms are also common in Pennsylvania corn fields. They are similar in appearance to corn earworms, but they have a white inverted "Y" mark on their heads. Fall armyworms enter the ear through the husk and feed on the kernels and cob.

Western bean cutworms are less common than corn earworms and fall armyworms, but they can cause significant damage to corn ears. Western bean cutworms are typically brown or gray in color with a dark head. They enter the ear through the husk and feed on the kernels.

European corn borers are the least common of the four caterpillar species found in Pennsylvania corn ears. They are typically white or yellow in color with dark heads. European corn borers enter the ear through the husk and feed on the stalk and kernels.

Most Bt corn hybrids offer some protection against corn earworm, fall armyworm, and European corn borer. However, control is not 100%, and corn earworm is steadily evolving resistance to the main Bt toxins.

If you are seeing significant damage to your corn ears, it is important to identify the species of caterpillar responsible. This will help you determine the best course of action for controlling the pest.

Here are some tips for scouting for caterpillars in corn ears:

• Open husks and look for caterpillars.
• Look for holes in the husk, which may be signs of fall armyworm or European corn borer feeding.
• Look for frass (insect droppings) around the ear.
• Look for damage to the kernels.

If you find caterpillars in your corn ears, you may need to take steps to control the pest. Depending on the species of caterpillar and the severity of the infestation, you may need to use pesticides or other control methods.

Photo Credit: gettyimages-nes