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Soybean Sentinel Plot Program

Posted: August 24, 2016

As we receive more much-needed rain, reports continue to indicate very mild insect pressure and little disease. Grasshoppers and Japanese beetles are still the primary defoliators, but populations remain below the economic threshold (15-20% defoliation). 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 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.

Weekly Plot Reports

19 August – Franklin County – Kelly Patches

Growth Stage: R3-5

  • Bean leaf beetles – Severity: 5 (causing about 5-10% defoliation)
  • Potato leaf hopper – Severity: 1
  • Japanese beetles – Severity: 5 (causing about 5-10% defoliation)
  • Grasshoppers – Severity: 1
  • Green cloverworm – Severity: 2
  • Aphids - Severity: 1
  • Frogeye leaf spot - Severity: 1
  • Beneficial insects present: Lady beetles, spiders

18 August – Clinton County – Don Woodring

Near Mill Hall
Growth Stage: R5

  • Bean leaf beetles – Severity: 1
  • Japanese beetles – Severity: 4
  • Grasshoppers – Severity: 2
  • Green cloverworm – Severity: 2
  • Spotted Cucumber Beetle – Severity: 1
  • Brown Stinkbugs – Severity: 1
  • Aphids – Present at low levels
  • Beneficial insects present: Lady beetles

18 August – Clinton County – Don Woodring

Near Loganton
Growth Stage: R3-4

  • Bean leaf beetles – Severity: 1
  • Japanese beetles – Present at low levels
  • Cloverworm – Severity: 3
  • Spotted Cucumber Beetle – Present at low levels
  • Brown Stinkbugs – Severity: 2

1 August – Mercer County – Gary W. Micsky

Growth stage: R5 - R6

  • Plants 36 - 41 inch
  • Japanese Beetle - Severity: 1
  • Grasshopper - Severity: 1
  • Spider mites - Severity: 1
  • Thrips - Severity: 1
  • Beneficials observed at low levels: Lady beetle adults and larvae and honey bees
  • Slight brown spot on oldest leaves, but most plants are clean, healthy and vigorous
  • 3 isolated spots showing damage from livestock, bacterial blight and possible sudden death syndrome

22 August - McKean County - Heather Supplee

Disked, Planted, 15 inch Rows, 2nd Year Beans
Growth Stage: R4

  • Grasshopper Nymphs - Severity 1
  • Bean Leaf Beetle - Severity 1
  • Frog Eye Leaf Spot- Severity 1
  • Bacterial Leaf Blight - Severity 1

23 August – Crawford County – Joel Hunter

Growth stage: R5
Plants ~ 45 inch height

  • Insects: All insects are at very slight levels with defoliation well below 1%
  • Japanese Beetle - Severity: 1
  • Thrips - Severity: 1
  • Disease: Generally healthy appearance. Substantial growth and color with recent rainfall.

23 August – Erie County – Joel Hunter

Growth stage: R5
Plants ~ 42 inch height

  • Insects: All insects are at very slight levels with defoliation well below 1%
  • Japanese Beetle - Severity: 1
  • Thrips - Severity: 1
  • Spider mites - Severity: less than 1
  • No diseases observed, generally healthy appearance. Substantial growth and color with rainfall.

22 August – Potter County – Nicole Carutis/Heather Supplee

No-till, planted 30-in rows
Growth Stage: R3

  • Slugs – Severity: 1
  • Japanese Beetle - Severity: 1
  • Green Cloverworm – Severity: 1
  • Bacterial Leaf Blight – Severity: 1
  • Field is very clean

19 August- York County - John Rowehl

Growth stage: R5

  • Japanese Beetle – Severity: 1
  • Mexican Bean Beetles - Severity: 2
  • Bean Leaf Beetle – Severity: 1
  • Grasshoppers – Severity: 12
  • Bacterial blight - Severity: 2
  • Frogeye leaf spot - Severity 1 around perimeter of the field

22 August – Columbia County – Chris Houser/Joel Imgrund

Growth stage: R6

  • Grasshoppers – Severity: 3
  • Japanese beetles – Severity: 1
  • Septoria - Severity: 1

22 August – Northumberland County – Chris Houser/Joel Imgrund

Growth stage: R6

  • Bean Leaf Beetle – Severity: 1
  • Grasshoppers – Severity: 1
  • Septoria - Severity: 1

22 August – Union County – Chris Houser/Joel Imgrund

Growth stage: R6

  • Grasshoppers – Severity: 2
  • Japanese beetles – Severity: 1
  • Aphids - Severity: 1
  • No diseases noted
  • Beneficials: a few Lady beetles noted

18 August-Perry County- Liz Bosak

Growth Stage: R5

  • Grasshoppers- Severity: 1
  • Japanese beetles- Severity: 1
  • Spider mites- Severity: 1
  • Silver spotted skipper- Severity: 1
  • Beneficials- a few lady beetles
  • No diseases noted

19 August- Dauphin County- Liz Bosak

Growth Stage: R5

  • Grasshoppers- Severity: 1
  • Japanese beetles- Severity: 1
  • Silver spotted skipper- Severity: 1
  • Beneficials- a few lady beetles
  • Soybean vein necrosis virus- Severity: 1

Contact Information

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