Illinois Field Crop Applicators Practice Test

How do Japanese beetle adults damage corn plants?

1. By feeding on the roots

2. By coating the tassels and silks with honeydew

3. By feeding on the silks

4. By tunneling into the stalk

The correct answer is: By feeding on the silks

Japanese beetle adults cause damage to corn plants primarily by feeding on the silks. This feeding activity disrupts pollination, which is critical for kernel development in corn. When the silks are damaged, it can prevent the pollen from reaching the ovules, resulting in poor kernel set and ultimately reducing yield. Feeding on the silks is particularly damaging because the silks are essential for transferring pollen to the ears of the corn. If the silks are not fully intact and healthy, the ability of the plant to produce seeds is compromised, which can lead to significant economic losses in a corn crop. While the roots, tassels, and stalks of the corn plant can also be affected by various pests, Japanese beetles are specifically known for their tendency to feed on the silks rather than causing damage through these other means.