Monitoring sweet corn for pest moth activity can help reduce the number of insecticide applications. At Kentland Farm in Whitethorne, VA, we recently harvested the first of several tests, where we followed an IPM approach and compared it to sprays of the pyrethroid lambda-cyhalothrin 3 times per week during silking. We saw no difference in the level of control from an IPM approach- only spraying when needed and spraying the diamide Coragen first compared with the frequent lambda pyrethroid sprays. We will be harvesting multiple sites for this experiment and will share these when all of the data are in. Several commercial sweet corn farms are still being monitored around Virginia for corn earworm and fall armyworm. However, many fields have been harvested already and trapping has been discontinued. Moth Trap Catch Data are being recorded by: Katlyn Catron (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Accomack Co. & Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk (Westmoreland Co.); Laura Siegle (Amelia Co.); and Mark Sutphin (Frederick Co.).
This week we observed general drop-off in corn earworm moth catch at many locations, but a big jump in numbers in Rockingham County in the Shenandoah Valley. Fall armyworm moths never really amounted to anything this year. For corn earworm, moth trap catch of less than 1 per night means low pest pressure and sweet corn sprays can probably be spaced 5-6 days apart during silking. However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively, and a more frequent spray interval (every 3 or 2 days) is justified. Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):
Week of Aug 27 (avg) | ||||
Region | County | Field | CEW/night | FAW/night |
Eastern Shore | Accomack | ESAREC – cemetery | 3.1 | NA |
Eastern Shore | Accomack | ESAREC – woods | NA | NA |
Eastern Shore | Accomack | ESAREC – sweet corn | 2.5 | 0 |
Eastern Shore | Northampton | Bridge Tunnel | NA | NA |
Eastern Shore | Northampton | Capeville 1 | NA | 0 |
Eastern Shore | Northampton | Cape charles | NA | NA |
Eastern Shore | Northampton | Eastville | NA | 0.2 |
Eastern Shore | Northampton | Nassawaddox | NA | 0.4 |
Virginia Beach | Virginia Beach | Pungo 1 | NA | NA |
Piedmont | Amelia | Field 1 | NA | NA |
Piedmont | Hanover | Farm 1 | NA | 0.4 |
Piedmont | Hanover | Haynes | NA | NA |
Northern Neck | Westmoreland | Field 1 | 1.0 | 0.0 |
Northern Neck | Westmoreland | Field 2 | NA | NA |
Shenandoah Valley | Rappahannock | Field 1 | 2.7 | 0 |
Shenandoah Valley | Page | Field 1 | NA | NA |
Shenandoah Valley | Frederick | Farm 1 | 10.5 | 0 |
Shenandoah Valley | Frederick | Farm 2 | 15.5 | 0 |
Shenandoah Valley | Rockingham | Farm 1 | 18.1 | 0 |
Shenandoah Valley | Rockingham | Farm 2 | NA | NA |
New River Valley | Montgomery | KC | 0 | 0 |
New River Valley | Montgomery | KO1 | 1 | 0 |
New River Valley | Montgomery | KO2 | 1 | NA |
New River Valley | Montgomery | WF1 | 0 | NA |
New River Valley | Montgomery | WF2 | 0 | NA |
New River Valley | Montgomery | WF3 | 0 | NA |
New River Valley | Montgomery | WS1 | 1 | NA |
New River Valley | Montgomery | WS2 | 0 | NA |
New River Valley | Montgomery | WS3 | 1 | NA |
Southwest | Carroll | NA | NA |