Soybean Sentinel Plot Report: August 19, 2025

Aug 20, 2025

By John Tooker, Ph.D.

Overview of reports from around Pennsylvania

This week we have ten reports from ten counties, even though our regular scouting efforts were disrupted by Ag Progress Days. The fields we scouted are approaching maturity; they were in growth stages R4 and R5. Insect and pathogen populations remain low. The insects that we found are typical for this time of year and included Japanese beetle, grasshoppers, and green cloverworm, among others. Septoria brown spot and frogeye leaf spot were the most common diseases but their populations were mostly low, probably due to dry conditions. 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 your 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

18 August July 2025 – Centre County – Adriana Murillo-Williams

Field near Bellefonte
Growth stage: R5

  • Bean lean beetle – Severity: 1
  • Japanese beetle – Severity: 1
  • Green cloverworm – Severity: 1
  • Grasshoppers – Severity: 1
  • Brown marmorated stink bug – Severity: 1
  • Silver spotted skipper – Severity: 1
  • White-tailed deer – Severity: 1
  • Downy mildew – Severity: 1
  • Frogeye leaf spot – Severity: 1
  • Soybean vein necrosis – Severity: 1

Source : psu.edu
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