Soybean Sentinel Plot Report: July 26, 2022

Summary of reports:

The reports this week indicate that insect populations are mostly low, but in some places, populations are creeping up to potentially concerning levels. Of particular concern are populations of grasshoppers and Japanese beetle, two types of insects that do well in hot and dry conditions, that appear to be approaching economic threshold in some areas. While soybean pods are small and soft, the economic threshold for leaf defoliation is 15% across an entire field—this level is being approached in the fields we are scouting in Adams, Mercer, Montgomery, York Counties. I recommend that you scout your fields to assess current feeding levels of grasshopper and Japanese beetles to determine if your crops need to be protected.

For diseases, dry weather continues to be keeping many diseases in check, but Septoria brown spot is being found at low levels. Good luck with your scouting

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").

Reports

26 July 2022 – Montgomery County – Andrew Frankenfield

Near Souderton

Growth stage: R1

• Japanese beetle – Severity: 2
• Grasshopper beetle – Severity: 2
• No diseases of note
• Drought stress evident

25 July 2022 – York County – Heidi Reed

Two fields, one near West York, one near Stewartstown

Growth stage: R3

• Japanese beetle – Severity: 1-2
• Mexican bean beetle – Severity: 3 (Stewartstown)
• Grasshopper – Severity: 1
• Beneficial insects active: Robber flies (Stewartstown)
• Downy mildew – Severity: 1 (Stewartstown)
• Septoria brown spot – Severity: 1 (West York)
• Frogeye leaf spot – Severity: 1 (West York)

25 July 2022 – Adams County – Heidi Reed

Near Littlestown

Growth stage: R4

• Japanese beetle – Severity: 1
• Grasshopper – Severity: 1-2
• Downy mildew – Severity: 1-2

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

Near Independence

Growth stage: R2

• Brown marmorated stink bug – Severity: 1
• Sudden death syndrome – Severity: 1
• Deer damage evident

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

Near Saxonburg,

Growth stage: R2

• Grasshopper – Severity: 1
• Japanese beetle – Severity: 1
• Cercospora leaf blight – Severity: 1

25 July 2022 – Somerset County – Leanna Dupptstadt

Field near Somerset

Growth stage: R2

• Japanese beetle – Severity: 1
• Bean leaf beetle – Severity: 1
• Grasshopper – Severity: 1
• Potato leafhopper – Severity: 1
• Redheaded flea beetles – Severity: 1
• No diseases of note

25 July 2022 – Bedford County – Leanna Dupptstadt

Field near Fishertown

Growth stage: R3

• Japanese beetle – Severity: 1
• Bean leaf beetle – Severity: 1
• No diseases of note
• Beneficial arthropods present: fireflies, spined soldier bug

22 July 2022 – Mercer County – Joey Akins

North of Mercer

Growth stage: R3

• Japanese beetle – Severity: 2
• Bean leaf beetle – Severity: 1
• Grasshopper – Severity: 2
• Brown marmorated stink bug – Severity: 1
• Soybean looper – Severity: 1
• No diseases of note

22 July 2022 – Berks County – Sarah Frame

Near Brownsville

Growth stage: R2

• Soybean aphid – Severity: 1
• Grasshopper – Severity: 1
• No diseases of note

21 July 2022 – Chester County – Sarah Frame

Two fields, one near South Pottstown, one near Parkesburg

Growth stage: R4

• Grasshopper – Severity: 1
• Japanese beetle – Severity: 1
• Mexican bean beetle – Severity: 1
• Soybean aphid – Severity: 1
• Septoria brown spot – Severity: 1

21 July 2022 – Centre County – Adriana Murillo-Williams

Field between Bellefonte and State College

Growth stage: V7+

• Bean leaf beetle – Severity: 1

• Grasshopper – Severity: 1
• Silver-spotted skipper caterpillar – Severity: 1
• Japanese beetle – Severity: 1

• No diseases of note