Japanese Beetle Numbers Increasing in Corn, Soybean

Jul 10, 2024

Missouri corn and soybean growers are reporting growing numbers of Japanese beetles in crops in recent weeks, says University of Missouri Extension state entomologist Ivair Valmorbida.

Valmorbida uses numbers from MU Extension’s Pest Monitoring Network, which gathers information from across the state

The highest numbers are reported in northwestern Missouri’s Gentry County. Numbers are also growing in northeastern Missouri. Japanese beetle adults are highly mobile, so Valmorbida recommends regular scouting of fields.

Adult Japanese beetles primarily feed on the upper canopy leaves, causing defoliation in soybean. Leaves become skeletonized with veins still intact.

In soybean, insecticide treatment decisions are based on growth stage and amount of defoliation, including injury from other defoliators because it is difficult to distinguish among the types of feeding injury.

Foliar insecticide treatment is recommended when defoliation is expected to exceed 30% before bloom (V1-R2 growth stages), 10% from pod development to pod fill (R3-R5) and 15% at the R6 (full seed) growth stage.

Japanese beetles are also considered a pest in corn crops. They focus on clipping corn silks necessary for pollination, which can lead to some yield reductions, says Valmorbida.

Valmorbida says foliar insecticide application is warranted in corn crops if the three following conditions are met:

There are an average of three or more beetles per ear.
Silks have been clipped to less than 0.5 inch.
Pollination is less than 50% complete.

MU Extension’s pest monitoring website offers an alert system for Japanese beetles and other pests. Subscribe to alerts at https://ipm.missouri.edu/pestMonitoring or email ipm@missouri.edu.

Valmorbida also recommends the following publications:

“Biology and Management of Japanese Beetle,” MU Extension, https://extension.missouri.edu/g7412.
“Biology and Management of Japanese Beetle in Corn and Soybean,” Oxford Academic, https://academic.oup.com/jipm/article/10/1/9/5454734.

Source : missouri.edu

Video: Independent Seed, National Impact | On The Brink: Episode 9

A survey of 200 independent seed businesses reveals what Canada's seed sector actually contributes — and what it stands to lose.

On the Brink, Justin Funk, a third-generation agri-marketer, shares the findings of a national survey conducted in early 2026. The numbers reframe the conversation: independent seed companies in Canada represent upwards of $1.7 billion in dedicated seed infrastructure, approximately 3,000 full-time equivalent jobs in rural communities, and an estimated $20 million in annual community contributions. And roughly 90% of Canada's cereals, pulses, and other small pollinated crops flow through them.

The survey also asked how dependent these businesses are on public plant breeding to survive. The answer was unambiguous. For policymakers evaluating the future of publicly funded breeding programs, Funk argues the economic case for this sector and the case for public plant breeding are the same argument.

On the Brink is a cross-country video series exploring the future of plant breeding in Canada. Each episode features voices from across the industry in an open, ongoing conversation about innovation and long-term investment in Canadian agriculture.