Pictured: Japanese beetles. Photo by K. Hamilton/DATCP
Emergence of the destructive Japanese beetle has started unusually early this season. A resident near Cross Plains in Dane County photographed a beetle on June 2, according to a report from UW-Madison Entomologist PJ Liesch.
The early appearance of this pest has likely been influenced by this spring’s warmer and wetter-than-normal conditions and signals for fruit growers and gardeners to begin making preparations to protect sensitive trees and garden plants from beetle feeding.
Beetle populations will continue to increase in the next two months, with peak activity occurring by late July. During the primary emergence and damage period ahead, residents can expect to see beetles consuming a wide range of landscape ornamentals, field crops, fruits, vegetables, and trees. Favored hosts include basil, birch, grape, linden, mountain ash, plum, and rose.
One of the most effective deterrents used by fruit and vegetable growers in DATCP’s pest monitoring networks is simple barrier netting (0.25 inch or less mesh). The nylon mesh netting can protect smaller plants such as berries, vegetables, herbs, shrubs, and young trees, as long as it fully covers plants and the edge of the mesh is secured to the ground. Netting should be in place by late June and maintained though harvest or until beetle populations decline in August.
Learn more about controlling the Japanese beetle: https://hort.extension.wisc.edu/articles/japanese-beetle/
