News

Soybean Sentinel Plot Report: July 12, 2022

Grasshoppers and bean leaf beetles are common, but generally, insect populations remain low while diseases are becoming more evident.

Updated:

July 12, 2022

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Japanese beetles are among the most common pests being found in our soybean sentinel plots (Photo by Leanna Duppstadt, Penn State Extension).

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Summary of reports:

The reports this week indicate that insect populations are growing and diversifying, but still remain below economic thresholds. Grasshoppers and Japanese beetles (Figure 1) dominate reports, but other insects are easily found. The hot and dry conditions are preferred by grasshoppers and may facilitate spider mite populations, though none were reported from our fields.

For diseases, Septoria brown spot was most common, but others, like soybean vein necrosis (Figure 2), downy mildew, and Cercospora leaf blight, were found. Hot, dry conditions make keep many diseases in check, but scout your own fields to know what is active. Good luck!

Figure 2: Soybean vein necrosis was found in one of our soybean sentinel plots (Photo by Anna Busch, Penn State Extension).

Background

This growing season the Pennsylvania Soybean Promotion Board is funding a Soybean Sentinel Plot Program, which is being managed by The Dept. 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").