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Soybean Sentinel Plot Program Update for August 10th, 2016

Posted: August 10, 2016

Reports continue to indicate mild insect pressure and little disease. Grasshoppers and bean leaf beetle appear to be the populations that are causing most significant defoliation with some fields approaching by not yet exceeding the economic threshold (15-20% defoliation).

For diseases, Septoria and frogeye are present in some fields, but well below concerning levels. Low populations of bacterial pustule are present is some fields; if populations grow, growers need to remember that a fungicide will not help against a bacterial disease! We expect these results to represent the majority of soybean fields in PA, but scout your fields to find out for yourself.

The Pennsylvania Soybean Promotion Board is funding a Soybean Sentinel Plot Program, which is being managed by Penn State Extension and The Department of Entomology at Penn State. In this effort, Penn State Extension Educators are regularly scouting 25 or so ‘typical’ soybean fields in nineteen counties across the state, reporting the populations of plant pathogens and insect pests that they find. Our goal is to keep folks aware of pests so that they will then scout their fields as part of an IPM program. It would be imprudent to use these reports as the basis or justification for an insecticide application or including insecticides in with a post emergence herbicide application.

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. Growers should be sure to check their own fields to determine your local populations, but these reports will give you a sense of what pests are active in fields. Our reports are distributed via this weekly newsletter, Penn State’s Field Crop News, and will be available in the next day or two on Penn State’s Field Crop Entomology website.

Sentinel Plot Reports

9 August – Crawford County

Joel Hunter

Growth stage: R3

  • Japanese beetle – Severity: 1
  • Spider mites – Severity: 1
  • Thrips – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Bacterial Pustule – Severity: 1

9 August – Erie County

Joel Hunter

Growth stage: R3

  • Japanese beetle – Severity: 1
  • Spider mites – Severity: 1 (counts significantly reduced with recent rain)
  • Thrips – Severity: 1
  • No disease noted

9 Aug – Lancaster County

Jeff Graybill

Near Manheim
Growth stage: R3

  • Japanese Beetle – Severity: 1
  • Grasshopper – Severity: 2
  • Bean Leaf Beetle – Severity: 4 (Defoliation 10-15%, close to threshold)
  • Septoria Brown Spot – Severity 1 (small amount in the lower canopy)
  • Frogeye Leaf Spot – Severity 1 (small amount in the lower canopy)
  • Few Glyphosate resistant Marestail emerging

8 August – Potter County

Nicole Carutis/Heather Supplee

No-till, planted 30-in rows
Growth Stage: R2

  • Bean leaf beetle – Severity: 1
  • Phyllosticta leaf spot – Severity: 1
  • Bacterial leaf blight – Severity: 1

8 August – Potter County

Nicole Carutis/Heather Supplee

No-till, planted 30-in rows
Growth Stage: R2

  • Japanese beetle – Severity: 1
  • Grasshopper – Severity: 1
  • Bacterial leaf blight – Severity: 1
  • Bumble and honey bees very active

8 August – Lancaster County

Del Voight / Emily Heilinge

Growth stage: R2-4

  • Bean leaf beetle – Severity: 1
  • Japanese beetle – Severity: 1-2
  • Grasshopper – Severity: 1
  • Mexican bean beetle – Severity: 1
  • Stinkbug: 1% damage

8 August – Lebanon County

Del Voight / Emily Heilinge

Growth stage: R5-7

  • Bean leaf beetle; – Severity: 1
  • Japanese beetle; – Severity: 1-2
  • Grasshopper – Severity: 1
  • Mexican bean beetle – Severity: 1
  • Stinkbug – Severity: 1

8 August – Bradford County

Mark Madden / Mason Tate

Near Ulster
Growth stage: R4

  • Japanese beetle – Severity: 2
  • Grasshopper – Severity: 1
  • Good lady beetle population present

8 August – Schuylkill County

Dwane Miller

Growth stage: R4

  • Japanese Beetle – Severity: 2
  • Bean Leaf Beetle – Severity: 1
  • Septoria Brown Spot – present on lowest leaves in canopy

8 August – Columbia County

Chris Houser/Joel Imgrund

Growth stage: R5

  • Bean Leaf Beetle – Severity: 2
  • Grasshopper – Severity: 3
  • Japanese beetle – Severity: 2
  • No disease observed

8 August – Northumberland County

Chris Houser/Joel Imgrund

Growth stage: R5

  • Bean Leaf Beetle – Severity: 1
  • Grasshopper – Severity: 1
  • Japanese beetle – Severity: 2
  • No disease observed

8 August – Union County

Chris Houser/Joel Imgrund

Growth stage: R5

  • Bean Leaf Beetle – Severity: 1
  • Grasshopper – Severity: 6
  • Japanese beetle – Severity: 3
  • No disease observed

7 August – Mercer County

Gary W. Micsky

Growth stage: R4-5

  • Japanese beetle – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Aphids – Severity: 1
  • Beneficials: honeybees and lady beetles present
  • No diseases observed, beans clean, healthy, and vigorous

4 August - York County

John Rowehl

Growth stage: R4-5

  • Japanese beetle – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Mexican bean beetles – Severity: 1
  • Bacterial blight - Severity: 2

4 August – Franklin County

Kelly Patches

Near Greencastle
Growth Stage: R4-5

  • Bean leaf beetle – Severity: 1 (causing about 5-10% defoliation)
  • Japanese beetle – Severity: 1 (causing about 5-10% defoliation)
  • Grasshopper – Severity: 1
  • Green cloverworm – Severity: 2
  • Potato leaf hopper – Severity: 1
  • Two-spotted spider mites – Severity: 1
  • Velvet bean caterpillars – Severity: 1
  • Beneficial insects present: Lady beetles and spiders

4 August – Clinton County

Don Woodring

Two fields
Growth stage: One field at R1, the other at R4

  • Bean leaf beetle – Severity: 1
  • Grasshopper – Severity: 2
  • Japanese beetle – Severity: 3
  • Green cloverworm – Severity: 1
  • Brown stinkbug – Severity: 1
  • Soybean aphid – Severity: 1
  • Lady beetles and honey and bumble bees present
  • No diseases noted

Contact Information

John Tooker
  • Extension Specialist
Phone: 814-865-7082