Japanese Beetles Invading Minnesota Gardens

An increasing number of Japanese Beetles have been spotted in farms and gardens throughout Minnesota and entomologists warn there could be more arriving in the coming months. According to University of Minnesota, this situation is the worst in five years.

Low temperatures during spring help control beetle populations. For instance, the particularly cold and wet spring of 2011 helped diminish Japanese Beetle populations across a large area of the midwest. Experts suggest that a shift in weather patterns may have led to a deviation from the normal growth pattern among segments of these invasive insects.

Japanese Beetles first appeared in the United States in the early 1900s, having been accidentally introduced in New Jersey. They were later discovered in Minnesota in the early 1990s. Although the insects do not kill plants exhaustively, in large numbers they can chew growing plants enough to hinder their development. What a lot of experts find worrying is the fact that the insects feed on more than 300 species of plants.

With the sudden population boom, different segments of the beetles will start a feeding frenzy, most likely targeting their favorite foods such as vines, grapes, roses, apples, and linden trees. This will undoubtedly create a problem for farmers and landowners. 

Japanese Beetles emerge from the soil in early July and remain out through September. Gardeners should start treating plants for grabs as well as adult Japanese Beetles. Insect traps can be used to control movement, but a more effective method is the combination of certain treatments and the use of vacuums.

When treating younger insects in the ground, experts suggest using GrubEx. The adults may not be deterred by the product, but farmers have reported better results using it against adult Japanese Beetles.