Menu

Scout Fields Now for Japanese Beetles

Farmers and homeowners should be on the lookout for Japanese beetles, say University of Missouri Extension specialists. Beetles have been found in most parts of the state.
Numbers are expected to peak in mid-July.

MU Extension horticulture and agronomy specialist Todd Lorenz tells farmers to scout their fields now. He monitors beetles in Cooper, Boone, Pettis and Howard counties and has seen numbers increase steadily in June.

Retired MU entomologist Ben Puttler says this year’s population appeared two weeks earlier than normal. “Two more full weeks of emerging beetles will play havoc,” Puttler says. In mid-Missouri, beetles skeletonize tops of ornamental trees such as Linden trees.

Japanese beetles also damage fruit trees and field crops. They feed on green corn silks and tassels, soybean leaves, and alfalfa forage.

Beetles are in the colonization stage in Missouri. At present, most rural areas of Missouri will see increasing populations as the pest disperses and establishes itself throughout the state, Puttler says.

“There are no known natural enemies to reduce beetle populations in the state and none are on the immediate horizon,” he says.

Adult Japanese beetles are metallic green in color with bronze- or copper-colored wing covers. They are about one-half inch long and have 12 white tufts of hair or bristles around the edge of the shell. Without magnification, these are seen as white dots. The adults usually emerge from the soil in late May or early June and reach peak numbers in June and early July. Numbers decrease in August.

Host plants develop a lacelike texture on leaves. The beetles damage corn tassels and developing silks, reducing yield.

Lorenz suggests applying an insecticide treatment to field corn during the silking period if there are three or more beetles per ear tip. Pollination should be less than 50 percent. In soybean, treatment is justified if foliage feeding exceeds 20-30 percent before bloom and 10-20 percent from bloom through pod fill. Use lower threshold numbers if plants are drought-stressed.

For more information from MU Extension on Japanese beetles, go to http://ipm.missouri.edu/pestMonitoring/jb.

Source: Todd Lorenz, University of Missouri

Recent News

Manure Nitrogen Use for Increased Profit and Environmental Protection
2/17/2020

Land application of organic materials is important in Nebraska. This article builds on an earlier CropWatch article. Since then, the data were further analyzed and the results further interpreted. This article avoids much repetition of the 2019 article but gives some new or revised information. Land application of manure and other organic materials supplies much N […]

This Is Grain Bin Safety Week
2/17/2020

U.S. Secretary of Agriculture Sonny Perdue issued a proclamation naming February 16-22 as Grain Bin Safety Week. Earlier this week, the Secretary sat down with the Governor of South Dakota, Kristi Noem, to talk about the importance of grain bin safety on the farm. Governor Noem grew up on a farm in Hamlin County, South […]

USDA Agricultural Projections to 2029-Focus on Corn, Soybeans
2/17/2020

On Friday, the U.S. Department of Agriculture released its 10-year projections for the food and agricultural sector.  The report noted that, “While agricultural crop prices are tending to trend upwards only slowly in nominal terms, U.S. trade disputes with China that existed at the time of these projections were formulated have dampened expectations, particularly for soybeans. These projections assume […]

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now