Author Archives: Sean Malone

Corn earworm update for September 5, 2019

Average nightly black light trap captures of corn earworm moths this week were: Chesapeake=33; Greensville=13; Southampton=10; Suffolk=27. Hanover had 12 per night if averaged over the past 2 nights, but 3 if averaged over the entire week. Here is the table:

In our corn earworm pyrethroid resistance monitoring experiment (adult vial tests), the seasonal average is 36% survival to a 24-hour exposure of 5 micrograms of cypermethrin per vial.

Corn earworm update for August 29, 2019

Nightly corn earworm/bollworm moth averages for reporting black light trap stations this week were: Greensville=22; Prince George (Templeton)=12; Prince George (Disputanta)=10; Southampton=13; Suffolk=32. Please see the link to the table below and also compare this year’s Suffolk, VA numbers to the past several years.

I have seen a large number of corn earworm moths in our soybean at the Tidewater Agricultural Research & Extension Center in Suffolk this week. Remember to scout for larvae and use the threshold calculator for soybean: https://www.ces.ncsu.edu/wp-content/uploads/2017/08/CEW-calculator-v0.006.html

Our pheromone trap catches at Suffolk have also increased and we were able to conduct more adult vial tests for resistance monitoring using the pyrethroid cypermethrin. The average survival for this season is now 37%.

Corn earworm/bollworm update for August 15, 2019

Moth numbers from reporting black light trap stations dipped somewhat from the highs of last week; please see the table below for more details. However, what this does mean for soybeans that are in the flowering stage or later is to scout for corn earworm larvae and use the online threshold calculator https://www.ces.ncsu.edu/wp-content/uploads/2017/08/CEW-calculator-v0.006.html with information specific to your fields. Please keep scouting in cotton, peanut, and other crops, too. Here is the black light table:

Corn earworm update for August 8, 2019

Black light trap catches of H. zea (corn earworm/bollworm) moths increased at most locations this week. Please see the data table for more information.

We have tested 168 corn earworm moths in our cypermethrin vial tests so far this season, with a seasonal average of 39.5% survival. Here are the results by month (we’ll be conducting more tests throughout August):

We have updated our corn earworm survey of field corn (as a predictor of infestation risk in other crops such as soybean) to include Rockingham County’s 10.8% infested ears. Thanks to all cooperators for their efforts. Statewide average infested ears was 15.3% for 2019. The updated table and map are here:

Corn earworm update, including field corn survey results, for August 1, 2019

Corn earworm moth catches are increasing for most black light stations; nightly averages this week were: Greensville=25.1; Prince George (Templeton)=5.7; Prince George (Disputanta)=3.7; Warsaw=46.4; Southampton=9.0; Suffolk=14.6.

Preliminary results from our annual survey of field corn show the following percent infested ears (based on sampling 5 corn fields/county, 50 ears per field, for evidence of corn earworm larvae): Accomack=16.0 percent infested ears; Amelia=15.6; Chesapeake=5.6; Dinwiddie=19.6; Essex=11.6; Greensville=32.8; Hanover=32.8; Isle of Wight=17.6; King & Queen=13.6; King William=24.4; Lancaster=4.8; Northampton=11.2; Northumberland=4.0; Prince George=12.8; Southampton=11.2; Virginia Beach=17.6; Westmoreland=12.8. Thanks to the following for collecting data from their counties: Eastern Shore AREC entomology; Laura Siegle; Watson Lawrence; Mike Parrish; Robbie Longest and Brittany Semko; Sara Rutherford; Laura Maxey-Nay; Livvy Preisser; Trent Jones; Scott Reiter; Joshua Holland; Roy, Bailey, and Fletcher Flanagan; and Stephanie Romelczyk and Amerah Thompson.

We have found bollworm eggs and small larvae in our cotton experiment in Suffolk. Please be sure to scout your fields.

Corn earworm report for July 18, 2019

Very low numbers of corn earworm moths were reported by our network of black light trap operators this week. Nightly averages ranged from 0.3 to 1.0 moths. Here are this week’s numbers (trap operators listed in parentheses):

Greensville (Sara Rutherford): 0.7 per night

Hanover (Laura Maxey-Nay): 0.9 per night

Prince George-Templeton (Scott Reiter): 0.8 per night

Prince George-Disputanta (Scott Reiter): 0.5 per night

Richmond County-Warsaw (Mary Beahm): 0.3 per night

Southampton (Josh Holland): 0.3 per night

Suffolk (Sally Taylor and crew): 1.0 per night

Here is a pdf of the data table: BLT_18_Jul_2019

We will be conducting vial tests to monitor insecticide resistance in corn earworm/bollworm again this year, but so far we have only captured and tested a handful of moths.