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Soybean Sentinel Plot Report: August 5, 2025

Disease and insect pressure remain low across the state.

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Updated:

August 5, 2025

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A grasshopper in soybeans (Photo by Anna Hodgson, Penn State)

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Overview of reports from around Pennsylvania

We have eight reports this week from extension educators in ten counties. Their reports cover fields from growth stage R2 to R5, late flowering to pod fill stages. The reports indicate low pest populations in the soybean fields that we are scouting, but there are a few instances where deer are problematic. Our reports identify Japanese beetle, grasshoppers, and green cloverworm as the main insect pests that are active; these are typical for this time of year. Mexican bean beetle has been showing up in southern counties. Diseases are becoming more prevalent but remain in low abundance. Our reports indicate downy mildew, frogeye leafspot, and Septoria brown spot as the main diseases present; these are typical for this time of year. Scout your own fields to learn what is active in your area. Good luck!

Background on the Project

This growing season, the Pennsylvania Soybean Promotion Board is funding a Soybean Sentinel Plot Program, which is being managed by the Department of Entomology at Penn State and executed by Penn State Extension. In this effort, Penn State Extension Educators are regularly scouting about 25 'typical' soybean fields in about 20 counties across the state, reporting the populations of plant pathogens and insect pests that they find. Our goal is to inform the agricultural community about which pests are active across the state, so folks will have a sense of what to expect when they scout their own fields as part of an IPM program. It would be inappropriate to use these reports to justify insecticide applications.

In the reports below, pests that were found during scouting are listed with their severity, which is rated on a 1–10 scale with 10 being the highest. A severity score of 1 equates to 10% or less infestation or defoliation, a "2" aligns with 20% or less infestation or defoliation, and so on. Growers should be sure to check their own fields to determine their local populations, but these reports will indicate which pests are likely to be active in fields. Our reports are distributed via this weekly newsletter and are available via the Penn State Extension website (then search for "soybean sentinel plot").

Reports

August 1, 2025 - Lebanon County - Del Voight/Tyler McFeaters

Three fields: one near Buffalo Springs, one near Cornwall, one near Rexmont

Growth Stage: R2-R5

Brown marmorated stinkbug – Severity: 1 (Buffalo Springs only)
Grasshoppers – Severity: 1
Green cloverworm – Severity: 1 (Buffalo Springs and Rexmont only)
Japanese beetle – Severity: 1
Mexican bean beetle – Severity: 1 (Buffalo Springs and Cornwall only)
Silver-spotted skipper – Severity: 1 (Buffalo Springs and Rexmont only)
Soybean aphid – Severity: 1 (Buffalo Springs only)
Beneficials present: braconid wasps (Buffalo Springs only), lady beetles (Buffalo Springs and Rexmont only)
Downy mildew – Severity: 1
Frogeye leafspot – Severity: 1 (Cornwall only)