Soybean Sentinel Plot Report: July 19, 2022

Summary of reports:

The reports this week indicate that insect populations remain low. Japanese beetle (Figure 1) and grasshoppers, which do well in hot, dry conditions, are common, but the leaf feeding we found in our fields remains below the economic threshold of 15% leaf removed during the early reproductive stages. The hot and dry conditions may promote certain pest species, so be aware of the risk by referring to our article on the topic from last week.

For diseases, dry weather seems to be keeping many diseases in check, but Septoria brown spot is becoming more common and others are likely to emerge with recent higher humidity. Good luck!

Background

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

19 July 2022 – Montgomery County – Andrew Frankenfield

Near Souderton

Growth stage: R1

• Japanese beetle – Severity: 1
• No diseases of note
• Drought stress evident

18 July 2022 – Washington County – Leanna Dupptstadt / Adam Hohn

Near Independence

Growth stage: R2

• Grasshopper – Severity: 1
• Japanese beetle – Severity: 1
• Sudden death syndrome – Severity: 1
• Groundhog and deer damage evident

18 July 2022 – Somerset County – Leanna Dupptstadt

Field near Somerset

Growth stage: R1

• Japanese beetle – Severity: 1
• Grasshopper – Severity: 1
• Redheaded flea beetles – Severity: 1
• Beneficial species active: spiders
• No diseases of note

18 July 2022 – Bedford County – Leanna Dupptstadt

Field near Fishertown

Growth stage: R2

• Japanese beetle – Severity: 1
• Grasshopper – Severity: 1
• No diseases of note
• Beneficial arthropods present: fireflies

18 July 2022 – Lancaster County – Jeff Graybill

Near Manheim

Growth stage: R2

• Grasshopper – Severity: 1
• Japanese beetle – Severity: 1
• Septoria brown spot – Severity: 1
• Sudden death syndrome – Severity: 1

18 July 2022 – Butler County – Justin Brackenrich / Adam Hohn

Two fields, one north of Saxonburg, one south of Saxonburg

Growth stage: R2 (South), R1 (North)

• Grasshopper – Severity: 1
• Japanese beetle – Severity: 1 (South)
• Septoria brown spot – Severity: 1 (South)
• Frogeye leaf spot – Severity: 1 (North)