Soybean Sentinel Plot Report: August 30, 2022

By JOHN TOOKER

Summary of reports:

The reports this week indicate that insect and pathogen populations in soybean fields for the most part remain mild, but there are some exceptions. In Adams County, for example, sudden death syndrome is affecting most of the field. With most fields reaching R6 and beyond, however, yield is mostly set, and farmers can worry less about pest species. For insect pests in our plots, grasshoppers and Japanese beetles were common, but their opportunity to influence plant productivity has passed. Once soybeans reach R4 and beyond, the economic threshold for insect defoliation is 30% defoliation across an entire field, so damage needs to be significant to justify an insecticide application that would require driving over part of the crop. For diseases, Septoria brown spot is common. Scout your fields to determine what is present and if populations are concerning. For information on implementing IPM in soybean fields, see our recently published fact sheet on the topic  .

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

29 August 2022 – Adams County – Heidi Reed

Near Littlestown

Growth stage: R6

• Sudden death syndrome – Severity: >5
• No insects of note

27 August 2022 – Potter County – Nicole Santangelo / Jack Thomas

Two fields, one near Ulysses, one south of Ellisburg

Growth stage: R6-7 (Ellisburg), Ulysses (R5)

• Japanese beetle – Severity: 1
• Grasshopper – Severity: 1
• Bean leaf beetle – Severity: 1 (Ellisburg)
• Brown marmorated stink bug – Severity: 1 (Ulysses)
• Soybean aphid – Severity: 1 (Ulysses)
• Septoria brown spot – Severity: 1
• Frogeye leafspot – Severity: 1 (Ulysses)
• Deer damage present

26 August 2022 – Chester County – Sarah Frame

Two fields, one near South Pottstown, one near Parkesburg

Growth stage: R6

• Two-spotted spider mite – Severity: 1 (Pottstown)
• Grasshopper – Severity: 1
• Septoria brown spot – Severity: 1-2
• Sudden death syndrome – Severity: 1-2 (Pottstown)

25 August 2022 – Beaver County – Justin Brackenrich / Adam Hohn

Near Fombell

Growth stage: R5

• Grasshopper – Severity: 1
• Green stink bug – Severity: 1
• Japanese beetle – Severity: 1
• No diseases of note
• Deer damage present

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

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

Growth stage: R6

• Grasshopper – Severity: 1
• Green cloverworm – Severity: 1
• Brown marmorated stink bug – Severity: 1 (North)
• Soybean aphid – Severity: 1 (North)
• Japanese beetle – Severity: 1
• Sudden death syndrome – Severity: 1 (North)
• Frogeye leaf spot – Severity: 1 (North)

23 August 2022 – Somerset County – Leanna Dupptstadt

Field near Somerset

Growth stage: R6

• Japanese beetle – Severity: 1
• Green stink bug – Severity: 1
• Bean leaf beetle – Severity: 1
• Grasshopper – Severity: 1
• Frogeye leaf spot – Severity: 1
• Downy mildew – Severity: 2

23 August 2022 – Bedford County – Leanna Dupptstadt

Field near Fishertown

Growth stage: R6

• Japanese beetle – Severity: 1
• Grasshopper – Severity: 1
• Frogeye leaf spot – Severity: 1
• Downy mildew – Severity: 1