News

Soybean Sentinel Plot Report: June 14, 2022

Early season pests like bean leaf beetle are active, as are soybean aphids.

Updated:

June 14, 2022

Figure 1. Soybean aphids on the underside of a soybean leaf from Berks County (Photo by Sarah Frame, Penn State Extension)

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Overview of reports from around Pennsylvania

The nine reports this week reveal a wider variety of pests in soybean fields than last week. Typical early-season pests, like bean leaf beetle and Mexican bean beetle, are active in low numbers, but we also have our first reports of silver-spotted skipper caterpillars and soybean aphid (Figure 1). Soybean aphid normally arrives in July, so this appearance is a bit unexpected. Back from 2001 to 2011, about every other year soybean aphid populations grew large enough to cause yield loss. But ever since, they have been present only in low numbers. At this early stage in their establishment, natural enemies are key for limiting populations. Do all you can to maintain populations of lady beetles, harvestmen, minute pirate bugs and other species; in other words, limit unnecessary insecticide applications, which are particularly hard on beneficial species, and can allow aphid populations to grow unchecked. As the season progresses, I encourage folks to scout soybean fields regularly to monitor aphid populations and use Integrated Pest Management to manage them should populations approach the economic threshold of 250 aphids per plant. Soybean aphid populations start on young leaves, and can usually be found on the underside of leaves, typically at the top of plants (Figure 1). For more information see our Soybean Aphid fact sheet.

Diseases have yet to develop in the fields we are scouting. 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 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").