PestWatch Report - August 30, 2017

Corn earworm counts spiked to a 3-4 day threshold in Erie, Fayette, Lycoming, Washington, Westmoreland, and York Counties.
PestWatch Report - August 30, 2017 - News

Updated: October 31, 2017

PestWatch Report - August 30, 2017

Corn earworm counts increased in this farm in Montgomery County, PA. Photo: A. Frankenfield, Penn State

Corn earworm (CEW) counts continued to increase and spiked to a 3-4 day threshold in Erie, Fayette, Lycoming, Washington, Westmoreland, and York Counties (see table, which has data a bit more updated than the maps). Many additional sites along the west, south, and eastern portions of PA advanced to a 4-5 day spray interval. Counties more towards the center of the state were a bit lower, at a 5-6 day interval. Eggs take about 2-3 days to hatch, and 1st instar larvae an additional 2-3 days to move into the ear if you have a tight-husked cultivar. Therefore, if you are within 4-6 days to harvest, there is no need to use sprays to prevent CEW larvae in the ear.

European corn borer (ECB) counts are high in Luzern County. All other sites are low.

Fall armyworm (FAW) counts are high in Erie County, and in increased also occurred south of Pittsburgh. Sites in the mid-central portion of the state showed plant damage in the presence of low counts.

CountyFarm/Trap NameCEWCEWCEWECBECBECBFAWFAWFAW
15-Aug23-Aug30-Aug15-Aug23-Aug30-Aug15-Aug23-Aug30-Aug
BlairCurryville, PA021null00null02null
BlairHollidaysburg, PA020null00null37null
BlairTyrone, PA030null00null09null
BradfordBristol's Producenullnullnullnullnullnullnullnullnull
BradfordLarue's Producenullnullnullnullnullnullnullnull
BradfordShores Sisters Producenullnullnullnullnullnullnullnull
BucksBedminster247null30null
BucksBuckingham45null403null0
CentreHarnernullnullnullnullnullnullnullnullnull
CentreRock Springsnullnullnullnullnullnullnullnullnull
CentreStormstownnullnullnullnullnullnullnullnullnull
ClintonLoganton0null0633
ErieDudas Farm133392659
ErieMason15401272244112
FayetteDuda's Farm Inc.null4887null05null814
HuntingdonNew Morning Farm719.89.371.20
IndianaBrush Valley46291535
IndianaCreekside262800201
LancasterLandisville644.6414.43000
LancasterNeffsville2152.52127.92000
LancasterNew Danville8053382000110
LehighGermansvillenullnullnullnullnullnull0nullnull
LuzerneDrumsnull220null67510
LuzernePlainsnull2030null65
LycomingLinden0null00null0
LycomingMontoursville1null281null4.7
LycomingMuncy0null82.85null7
MontourMontournull817null84
NorthamptonNazarethnull1nullnull4nullnull00
SchuylkillTower City0010000004.7
WashingtonVenetia22.54686nullnull105null7
WestmorelandSchramms Farms and Orchard5.5null101.30null0
YorkYork4560155210006

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 absent1-134 days to no spray
very low14-355 to 6 day
low36-704 to 5 day
moderate71-3493 to 4 day
high> 3502 to 3 day

If CEW is low, then consider ECB

Levels ECB catch / week Spray frequency
almost absent< 14no treatment
very low15-356 day
low38-705 day
moderate> 704 day
high

Authors

Insect population dynamics IPM

More by Shelby Fleischer, Ph.D.