Soybean Sentinel Plot Report: August 25, 2026
Overview of reports from around Pennsylvania
This week, we have reports from extension educators from seventeen fields in nine counties. Their reports cover fields in growth stages spanning R3 to R6. This time of year, it is important to note the growth stage of soybeans because for most insects and diseases, there is usually no economic benefit to treating fields with insecticides and fungicides once they reach R6.Â
Our scouting continues to find low insect and disease populations. As usual for this time of year, our reports noted bean leaf beetle, grasshoppers, and Japanese beetle as the main insect pests that were active, but other species, including stink bugs, were found, but none at concerning levels. For diseases, we found a greater diversity this week, but downy mildew was most abundant, and some fields had white mold, which can be concerning. 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
24 August 2026 – Indiana County – Stephen Campbell
Field near Brush Valley
Growth Stage: R5
- Grasshopper – Severity: 1
- Japanese beetle – Severity: 1
- Frogeye leaf spot – Severity: 1
24 August 2026 – Columbia County – Anna Hodgson
Field near Mainville
Growth Stage: R6
- Bean leaf beetle – Severity: 1
- Brown marmorated stink bug – Severity: 1
- Grasshopper – Severity: 1
- Green stink bug – Severity: 1
- Frogeye leaf spot – Severity: 1
- Septoria brown spot – Severity: 1
24 August 2026 – Northumberland County – Anna Hodgson
Organic field near Riverside
Growth Stage: R1
- Bean leaf beetle – Severity: 1
- Grasshopper – Severity: 1
- Green cloverworm – Severity: 1
- Japanese beetle – Severity: 1
- Soybean aphid – Severity: 1
- Beneficial insects: damsel bugs, lady beetles, bumble bees
- Frogeye leaf spot – Severity: 1
- Septoria brown spot – Severity: 1
24 August 2026 – Franklin County – Tosh Mazzone
Field near Lemasters
Growth Stage: R6
- Bean leaf beetle – Severity: 1
- Grasshoppers – Severity: 1
- Green cloverworm – Severity: 1
- Japanese beetle – Severity: 1
- Silver spotted skipper caterpillar – Severity: 1
- Downy mildew – Severity: 1
24 August 2026 – Dauphin County – Ashley Isaacson
Field near Killinger
Growth Stage: R5
- Brown stink bug – Severity: 1
- Brown marmorated stink bug – Severity: 1
- Grasshopper – Severity: 1
- Green stink bug – Severity: 1
- Japanese beetle – Severity: 1
- Deer – Severity: 1
- No diseases noted
24 August 2026 – Northumberland County – Anna Hodgson
Field near Rushtown
Growth Stage: R6
- Bean leaf beetle – Severity: 1
- Grasshopper – Severity: 1
- Green stink bug – Severity: 1
- Japanese beetle – Severity: 1
- Silver spotted skipper caterpillar – Severity: 1
- Soybean aphid – Severity: 1
- Septoria brown spot – Severity: 1
- Soybean mosaic virus – Severity: 1
21 August 2026 – Cambria County – JohnMark Miller
Field near Patton
Growth Stage: R6
- Bean leaf beetle – Severity: 1
- Grasshopper – Severity: 1
- Japanese beetle – Severity: 1
- No diseases noted
21 August 2026 – Clarion County – JohnMark Miller
Field near Snively Corners
Growth Stage: R3
- Bean leaf beetle – Severity: 1
- Grasshopper – Severity: 1
- Downy mildew – Severity: 1
21 August 2026 – Jefferson County – JohnMark Miller
Two fields: one near Troutville, one near Sykesville
Growth Stage: R6
- Bean leaf beetle – Severity: 1
- Grasshopper – Severity: 1
- Japanese beetle – Severity: 1
- Mexican bean beetle – Severity: 1
- Deer – Severity: 1
- Groundhog – Severity: 1
- Downy mildew – Severity: 1
- Cercospora leaf blight – Severity: 1
18 August 2026 – Lebanon County – Del Voight / Brooke Coble
Three fields: one near Richland, others near Avon and Cornwall
Growth Stage: R5
- Grasshoppers – Severity: 1
- Green stink bug – Severity: 1
- Deer – Severity: 1
- Downy mildew – Severity: 1
- Frogeye leaf spot – Severity: 1
- White mold– Severity: 1
18 August 2026 – Franklin County – Tosh Mazzone
Field near Lemasters
Growth Stage: R5
- Grasshoppers – Severity: 1
- Green stink bug – Severity: 1
- Japanese beetle – Severity: 1
- Silver spotted skipper caterpillar – Severity: 1
- Slugs – Severity: 1
- Downy mildew – Severity: 1
18 August 2026 – Lebanon County – Del Voight / Brooke Coble
Four fields: one near Lebanon, others near Annville, Bordnersville, and Fredericksburg
Growth Stage: R3-R5
- Bean leaf beetle – Severity: 1
- Brown stink bug – Severity: 1
- Grasshoppers – Severity: 1
- Green stink bug – Severity: 1
- Silver spotted skipper caterpillar – Severity: 1
- Deer – Severity: 1
- Anthracnose stem blight – Severity: 1
- Downy mildew – Severity: 1
- Frogeye leaf spot – Severity: 1
- Pod and stem blight – Severity: 1
- Soybean mosaic virus – Severity: 1
- Sudden death syndrome – Severity: 1
- White mold– Severity: 1
