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Soybean Sentinel Plot Update

Posted: September 1, 2015

This week we have eight reports covering seven counties. Insect pressure remains low in most areas, though small populations of grasshoppers and Japanese beetles persist. Aphid populations seem to be declining, likely due to lady beetles swarming to a tasty meal. Disease pressure remains low, but can still be found. Happy scouting!

Weekly Summary

Soybeans appear to be senescing rapidly with the warm, dry weather, and the opportunity to economically manage any lingering pest populations is dwindling daily. Really, it is rare that spraying insecticides this time of year is useful because most fields are at R6 (or are fairly close it) when yield is set, and the yield hit from driving across the fields will likely outweigh the benefits of controlling the pesky insects.

About the Reports

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 twenty-two ‘typical’ soybean fields in sixteen counties across the state, reporting the populations of plant pathogens and insect pests that they find. 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.

31 August – Gary Micsky – Mercer County

Growth Stage: R6

  • Soybean aphid – Severity: 2
  • Beneficial insects active: Lady beetles and their larvae becoming increasingly abundant
  • 5-10% defoliation
  • Japanese beetle – Severity 1
  • Bean leaf beetle – Severity 1
  • Potato leafhopper – Severity 1
  • Minor brown spot with affected leaves dropping, pods filling out nicely
  • Minor deer and groundhog feeding

31 August – Mena Hautau – Berks County

Fleetwood field

Growth stage: R6

  • Green cloverworm – Severity: 1
  • Japanese Beetle – Severity: 2
  • Soybean aphid – Severity: 1
  • Brown marmorated stink bugs – Severity: 1
  • Grasshoppers – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Frog-eye leaf spot – Severity: 2

Kutztown field

Growth stage: R5

  • Bean leaf beetle – Severity: 1
  • Japanese Beetle – Severity: 1
  • Green cloverworm – Severity: 1
  • Soybean aphids – Severity: 1
  • Beneficial insects active: lady beetles, minute pirate bugs, lacewing larvae
  • Frog-eye leaf spot – Severity: 1

31 August – Joel Hunter – Crawford County

Growth Stage: R6

  • Soybean aphid: Severity: 1
  • Beneficial insects active: Lady beetles and their grubs becoming increasingly abundant
  • Japanese beetle – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Potato leafhopper – Severity: 1
  • Minor deer and groundhog feeding
  • Bacterial Pustule fairly common throughout mid- to lower- canopy Severity: 2-3

31 August – John Rowehl – York County

Growth Stage: R6

  • Japanese beetle – Severity: 1
  • Grasshoppers – Severity: 1
  • Brown marmorated stink bug – Severity: 1
  • Downy mildew – Severity: 1
  • Septoria brown spot – Severity: 1

31 August – Joel Imgrund – Columbia County

Growth Stage: R5

  • Japanese beetle – Severity: 2
  • Septoria brown spot – Severity: 1
  • Cercospora leaf blight – Severity: 1

31 August – Joel Imgrund – Northumberland County

Growth Stage: R6

  • Japanese beetle – Severity: 1
  • Grasshopper – Severity: 3
  • Brown marmorated stink bug – Severity: 2
  • Soybean aphids – Severity: 1
  • Beneficial insects active: Lady beetle larva (low abundance)
  • Septoria brown spot – Severity: 1

31 August – Joel Imgrund – Union County

Growth Stage: R6

  • Japanese beetle – Severity: 1
  • Grasshopper – Severity: 3
  • Soybean aphids – Severity: 1
  • Beneficial insects active: Lady beetle larva (low abundance)
  • Septoria brown spot – Severity: 3
  • Cercospora leaf blight – Severity: 1

1 Sept – Kelly Patches – Franklin County

Greencastle field

Growth Stage: R6

  • Brown marmorated stink bug – Severity: 1
  • Bean leaf beetle – Severity: 1
  • Grasshoppers – Severity: 2
  • Spiders also present

Contact Information

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