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Soybean Sentinel Plot Program

Posted: August 9, 2017

Reports this week from across the state indicate low pest populations in the soybean fields we are scouting. Our reports from this week identify Japanese beetles, and grasshoppers as the primary defoliators, but aphids and brown marmorated stink bugs are present in some fields. Remember that vegetative stages soybeans can tolerate up to 25% defoliation without dropping yield and reproductive stage beans can tolerate 15%. So do not overreact if you find some feeding damage in your fields. For diseases, reports of Septoria brown spot and frogeye leaf spot are present in some fields, but pest pressure is low.

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. 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 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.

Reports

8 August 2017 – Perry County – Liz Bosak

Growth stage: R2

  • Japanese beetle – Severity: 1
  • No diseases noted

8 August 2017 – Dauphin County – Liz Bosak

Growth stage: R3

  • Japanese beetle – Severity: 1
  • No diseases noted

8 August 2017 – Cambria County – Zach Larson

Near Loretto

Growth stage: R4-5

  • Japanese beetle – Severity: 1
  • Green cloverworm – Severity: 1
  • Bean leaf beetles – Severity: 1
  • Frog eye leaf spot – Severity: 1
  • Bacterial leaf blight – Severity: 1
  • Fireflies are active

8 August 2017 – Blair County – Zach Larson

Near Martinsburg

Growth stage: R4

  • Japanese beetle – Severity: 1
  • Green cloverworm – Severity: 1
  • Septoria brown Spot – Severity: 1

8 August 2017 – Armstrong County – Rachel Milliron

Growth stage: R3

  • Japanese beetle – Severity: 2
  • Bean leaf beetle – Severity: 2
  • Grasshoppers – Severity: 1
  • Septoria brown Spot – Severity: 1
  • Frog eye leaf spot – Severity: 1

8 August 2017 – Crawford County – Joel Hunter

Growth stage: R2-3

  • Japanese beetle – Severity: 1
  • Septoria brown Spot – Severity: 1

7 August 2017 – Elk County – Nicole Carutis/Mellissa Rathbun

Growth stages: R2

  • Japanese beetle – Severity: 1
  • Septoria brown spot – Present on older leaves only

7 August 2017 – Jefferson County – Nicole Carutis/Mellissa Rathbun

Growth stage- R1

  • Japanese beetle – Severity: 1
  • Grasshopper – Present
  • Frogeye leaf spot – Severity: 1
  • Bacterial Leaf Blight – Severity: 2

7 August 2017 – McKean County – Nicole Carutis/Mellissa Rathbun

Growth stages: R1

  • Japanese beetle – Present
  • Septoria brown spot – Present
  • Bacterial Leaf blight - Present
  • Many beneficials: lady beetle larvae & bumble bees

7 August 2017 – Columbia County – Chris Houser/Joel Imgrund

Growth stage: R4

  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 2
  • Green cloverworm – Severity: 1
  • No diseases noted

7 August 2017 – Northumberland County – Chris Houser/Joel Imgrund

Growth stage: R4

  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 2
  • Bean leaf beetles – Severity: 2
  • Potato leafhoppers – Severity: 1
  • Lady beetles present
  • No diseases noted

7 August 2017 – Union County – Chris Houser/Joel Imgrund

Growth stage: R3

  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 3
  • Bean leaf beetles – Severity: 1
  • Potato leafhoppers – Severity: 1
  • Green cloverworm – Severity: 1
  • No diseases noted

4 August 2017 – Franklin County – Kelly Patches

Near Greencastle

Growth stage: R3

  • Japanese beetle – Severity: 2
  • Green cloverworm – Severity: 2
  • Bean leaf beetle – Severity: 2
  • Potato leaf hopper – Severity: 1
  • Grasshoppers – Severity: 1
  • Soybean aphid – Severity: 1
  • Beneficial arthropods present: spiders
  • No diseases noted

4 August 2017 – Franklin County – Kelly Patches

Near Fayetteville

Growth stage: R3

  • A few weeks ago, field was sprayed with a post-emergent herbicide, and they unnecessarily include an insecticide
  • Japanese beetle – Severity: 1
  • Green cloverworm – Severity: 1
  • Potato leafhopper – Severity: 1
  • Beneficial arthropods present: spiders, green lacewings
  • No diseases noted

2 August 2017 – York County – John Rowehl/Tom Lockhart

Near southern Stewartstown

Growth stage: R4

  • Bean leaf beetle – Severity: 1
  • Grasshoppers – Severity: 1
  • Silver-spotted skipper caterpillars – Severity: 1
  • Japanese beetle – Severity: 1
  • Mexican bean beetles – Severity: 1
  • Septoria brown Spot – Severity: 1
  • Frog eye leaf spot – Severity: 1
  • Downy mildew – Severity: 1

2 August 2017 – York County – John Rowehl/Tom Lockhart

Near eastern Stewartstown

Growth stage: R3

  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 1
  • Mexican bean beetles – Severity: 1
  • Bean leaf beetles – Severity: 1
  • Brown marmorated stink bug – Severity: 1
  • Downy mildew – Severity: 1

2 August 2017 – York County – John Rowehl/Tom Lockhart

Near Windsor

Growth stage: R4-5

  • Silver-spotted skipper caterpillars – Severity: 1
  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 1
  • Bean leaf beetles – Severity: 1
  • Brown marmorated stink bug – Severity: 1
  • Downy mildew – Severity: 1

Contact Information

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