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PestWatch Report on July 6, 2017

Posted: July 7, 2017

Corn earworm (CEW) has been detected in all 30 trapping sites.
Fall Armyworm feeding in vegetative corn. Photo: S. Fleischer, Penn State

Fall Armyworm feeding in vegetative corn. Photo: S. Fleischer, Penn State

Although counts declined in most locations since last week, a site in Lycoming increased to suggest a 4-5 day spray interval, and sites in Blair, Fayette, Lehigh, Westmoreland and York have been above 4-5 day spray thresholds during the last 2 weeks. Silking corn will strongly attract egg-laying females.

 

 

County Trap Name 22-Jun 29-Jun 6-Jul
Blair Curryville, PA (Blair) null null 16
Blair Tyrone, PA (Blair) 51 null null
Bradford Bristol's Produce 0 0 0
Bradford Larue's Produce 0 2 null
Bradford Shores Sisters Produce 0 0 0
Bucks Bedminster 0 0 0
Bucks Buckingham null null 6
Centre Harner 2.3 null 0
Centre Rock Springs 2 null 1
Centre Stormstown 40.3 null 9.1
Clinton Loganton 0 0 0
Fayette Duda's Farm Inc. 15 20 null
Huntingdon New Morning Farm null 14.8 null
Indiana Brush Valley null null 1
Indiana Creekside 26 4 2
Lackawanna Ransom null 0 4
Lancaster Landisville 0 9 3
Lancaster Neffsville 6 9 0
Lancaster New Danville 5 7 2
Lehigh Germansville 4.7 22 24
Luzerne Drums 0 0 3
Lycoming Linden 2 0 1.8
Lycoming Montoursville 20 14 42
Lycoming Muncy 2 2.6 null
Montour Montour null 8 6
Northampton Nazareth 0 1 0
Schuylkill Tower City 1 0 1
Washington Venetia 47 35 16
Westmoreland Schramms Farms and Orchard null 27.1 null
York York 3 28 8

cew map 7-6

European corn borer (ECB)

Moth counts have declined to below threshold. Larvae generated from adults earlier in the season can be controlled with a spray timed at row tasel.

County Trap Name 22-Jun 29-Jun 6-Jul
Blair Curryville, PA (Blair) null null 0
Blair Tyrone, PA (Blair) 0 null null
Bradford Bristol's Produce 55 22 4
Bradford Larue's Produce 250.3 98 null
Bradford Shores Sisters Produce 43 17 13
Bucks Bedminster 0 0 0
Bucks Buckingham null null 8
Centre Harner 12.3 null 0.7
Centre Rock Springs 0 null 0
Centre Stormstown null null 0
Clinton Loganton 18 2.8 1.2
Fayette Duda's Farm Inc. 0 0 null
Huntingdon New Morning Farm null 2.3 null
Indiana Creekside 0 0 0
Lackawanna Ransom null 7 3
Lancaster Landisville 2 10 1
Lancaster Neffsville 4 8 0
Lancaster New Danville 1 0 1
Lehigh Germansville 11.7 21 0
Luzerne Drums 17 0 0
Montour Montour 1 14 3
Northampton Nazareth 16 2 0
Schuylkill Tower City 1 1 0
Westmoreland Schramms Farms and Orchard null 12.6 null
York York 0 0 8

ecb map 7-6

Fall armyworm (FAW)

We are starting to see low rates of trap capture. Some may be due to a nontarget (Leucania phragmatidicola) but early immigration may also be occurring now. It is not uncommon to find damage prior to trap capture at this time of year. Check for larval feeding in vegetative corn: large, ragged damage to leaves with lots of frass.

Although CEW declined in most locations, captures increased in Lycoming County, and have been about thresholds in much of the state in the last 2 weeks. ECB adult flight has decreased, but larval infestations may be present from earlier flight. We are also beginning to see FAW in the state, which will typically move first into vegetative corn at this time of year. Silking corn will be very attractive to early-season CEW moths.

Average weekly catch—a moving average for the last 7 days. The average catch per night (catch, divided by the number of nights trapping), divided by the number of nights where data exist, multiplied by 7. Weeks where all the average-catch-per-night values are nulls are treated as if no data exist for that week.

PestWatch website

spray count legend

Thresholds

Reproductive (tassel/silk) and late vegetative corn attracts moths. Shorten spray schedules when populations increase.

Thresholds Based on CEW Captures

Levels CEW catch / week Spray frequency
almost absent 1–13 4 days to no spray
very low 14–35 5 to 6 day
low 36–70
4 to 5 day
moderate 71–349 3 to 4 day
high > 350 2 to 3 day

If CEW is low, then consider ECB

Levels ECB catch / week Spray frequency
almost absent < 14 no treatment
very low 15–35 6 day
low 38–70 5 day
moderate > 70 4 day
high

Contact Information

Shelby Fleischer
  • Professor of Entomology
Email:
Phone: 814-863-7788