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Soybean Sentinel Plot Program

Posted: June 14, 2017

With the warm weather, soybean fields have made some good progress in the last week and have actually put on some growth. We have only a few reports from around the state so far, but they appear to indicate that slug populations are receding as they hide from the heat. Bean leaf beetles and silver-spotted skipper caterpillars have been found, but populations are low. Keep in mind that in their vegetative stages soybeans can tolerate up to 25% defoliation without dropping yield, so do not overreact if you find some feeding damage in your fields. For diseases, one field had what appeared to be the start of a Septoria brown spot population.

The Pennsylvania Soybean Promotion Board is funding a Soybean Sentinel Plot Program, which is being managed by Penn State Extension and The Dept. 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.

Scouting Reports

12 June 2017 – Blair County – Zach Larson

Near Martinsburg

Growth stage: V1

  • Slugs – Severity: 1

12 June 2017 – Cambria County – Zach Larson

Near Loretto

Growth stage: V1

  • No insects or diseases noted

12 June – Columbia County – Chris Houser/Joel Imgrund

Growth stage: V1

  • Bean leaf beetle – Severity: 1
  • No diseases noted

13 June – Lancaster County – Jeff Graybill

Growth stage: V1

  • Bean leaf beetle – Severity: 3  some scarring on cotyledon and feeding on unifoliate leaves
  • Slugs – Severity: 1 some feeding in low spots
  • No diseases noted

Field has some wet areas with reduced stands, but they look like they will fill in.

4-5 nodules developing at this time.

12 June – Northumberland County – Chris Houser/Joel Imgrund.

Growth stage: V1

  • Bean leaf beetle – Severity: 2
  • Slugs – Severity: 2
  • Silver spotted skipper – Severity: 1
  • No diseases noted

12 June – Union County – Chris Houser/Joel Imgrund

Growth stage: VE

  • Bean leaf beetle – Severity: 1
  • Slugs – Severity: 1
  • No diseases noted

8 June – York County – John Rowehl

York-Stewartstown

Growth stage: V1-V2

  • Bean leaf beetle – Severity: 1
  • Mexican bean beetle – Severity: 1
  • Slugs, some signs of feeding on cotyledons
  • Grass weeds are emerging, 1-2 “ tall – Severity: 1
  • No diseases noted

Contact Information

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