Soybean Sentinel Plot Report: September 16, 2025

By John Tooker

Overview of reports from around Pennsylvania

Dry conditions prevail across our region and is hastening the end of the growing season for soybean and many fields are starting to senesce and drop leaves (Figure 1), rendering insect pests of soybeans less relevant. Soybeans in the last reports from five counties are at growth stages R6 or later. While some insects were found, at this point they are not really pests—they are more like residents who will have to prepare for cooler temperatures and will exit soybean fields shortly. Pathogens were also found, but with leaves falling, they too are rapidly becoming less relevant.

This will be the final soybean report for 2025 on soybean insects and diseases. Thanks for following along with us as we scouted soybean fields across the state to track the pest complex from June until September. We will do it again next year. If you have suggestions that you think would make our scouting efforts more useful for you, please get in touch with your local, county-based agronomy educator or me. Please remember that understanding your local pest populations is a vital step for implementing integrated pest management (IPM) and deploying insecticides or fungicides so they will provide an economic benefit. For more information on implementing IPM in soybean fields, see our recently published fact sheet on the topic.

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.