Sweet corn moth trap numbers for VA counties – week of July 24, 2017

Sweet corn farms are being monitored around Virginia for the two most important pests attacking the ears, corn earworm and fall armyworm.  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.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

This week we observed some big jumps in corn earworm moth catch at some locations such as the Bridge Tunnel in Northampton County, the ESAREC in Accomack Co., and Hanover Co.   We still have not seen very many  fall armyworm moths yet, only a few moths here and there in VA. 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 July 24 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 9.6 1
Eastern Shore Accomack ESAREC – woods 3.4 0
Eastern Shore Accomack ESAREC – sweet corn 4.6 0
Eastern Shore Northampton Bridge Tunnel 60.4 NA
Eastern Shore Northampton Capeville 1 2.1 0
Eastern Shore Northampton Cape charles 6.3 NA
Eastern Shore Northampton Eastville 10.6 1
Eastern Shore Northampton Nassawaddox 0.1 1
Virginia Beach Virginia Beach Pungo 1 11.9 1
Piedmont Amelia Field 1 NA NA
Piedmont Hanover Farm 1 11.0 0.0
Piedmont Hanover Haynes 3.9 0.0
Northern Neck Westmoreland Field 1 6.3 0
Northern Neck Westmoreland Field 2 NA NA
Shenandoah Valley Rappahannock Field 1 0.6 0
Shenandoah Valley Page Field 1 1.7 0
Shenandoah Valley Frederick Farm 1 1.4 1
Shenandoah Valley Frederick Farm 2 5.2 0
Shenandoah Valley Rockingham Farm 1 0.7 1
Shenandoah Valley Rockingham Farm 2 NA NA
New River Valley Montgomery KC 0.0 0
New River Valley Montgomery KO1 2.0 1
New River Valley Montgomery KO2 6.0 1
New River Valley Montgomery WF1 1.0 NA
New River Valley Montgomery WF2 0.0 NA
New River Valley Montgomery WF3 4.0 NA
New River Valley Montgomery WS1 0.0 NA
New River Valley Montgomery WS2 1.0 NA
New River Valley Montgomery WS3 1.0 NA

This project is sponsored by a Specialty Crop Block Grant by VDACS.

Insect update for July 27, 2017

Corn earworm/bollworm moth captures in the black light traps increased this week, with averages ranging from 2 to 65 moths per night. Suffolk and Hanover had high numbers. Brown marmorated stink bugs ranged from zero to 10 per night across our reporting stations (high numbers in Hanover). More details can be found in the tables here: BLT_27_Jul

Be sure to scout your fields to keep aware of your pest situation. The 2017 Virginia Cooperative Extension Field Crops Pest Management Guide contains thresholds, sampling procedures, and products/rates for soybean (pages 4-61 to 4-76), peanut (pages 4-77 to 4-86), cotton (pages 4-87 to 4-100) and other crops. There is also an online threshold calculator for corn earworm in soybean

Results (to date) from Dr. Taylor’s corn earworm survey of field corn are as follows:  Accomack= 29% infested ears; Northampton=38%; Henrico=37%; Chesapeake=19%; Dinwiddie=19%; Greensville=19%; Prince George=20%; Southampton=53%; Sussex=26%; Amelia=18%; Lancaster=4%; Northumberland=7%; Richmond County=4%; Westmoreland=6%; and Franklin County=46% infested ears.

Small upsurge in kudzu bug populations

Kudzu bug has been spotted above threshold (1 nymph per sweep – use at least 15 sweep samples in multiple parts of the field) in south central Virginia and in parts of central North Carolina. Kudzu bugs typically move into soybean in July-August in our state. Distribution surveys conducted by the entomology department in 2016 showed that kudzu bug are present in many soybean growing regions of our state.

Please consider the following information before making the decision to spray for this pest.

  1. Wait until nymphs (nymphs are wingless and cannot fly) are present in the field. Adults can make multiple invasions into a field. You do not want to make repeated sprays for this pest.
  2. Insecticides labeled for kudzu bug are broad-spectrum and will kill beneficials in your field. We are experiencing a large and early corn earworm flight this year in Virginia. Worm pests are much more likely to be a problem in fields that have been previously sprayed.

I’ll keep you posted on what we are seeing in soybean throughout Virginia. Please call if you have something to report.

Sally 919-801-5366

Large bollworm flight this year into VA cotton

If blacklight traps at the Tidewater AREC in Suffolk are any indication, we are currently experiencing an unusually large and early bollworm (aka corn earworm) moth flight this year. Average trap catches over the past 4 nights have averaged 70 moths per night. I have included 2016 season-long catches below for comparison.

We have additionally scouted for, and found, eggs in cotton and on silks of late-planted corn. I have included pictures below to help with identification. Our ongoing corn earworm survey has revealed large numbers of worms completing development on Bt corn in multiple counties. I strongly encourage cotton growers who planted Widestrike or Bollgard II this year to be vigilant when scouting fields. In agreement with Dominic Reisig’s (North Carolina State University) 2016 recommendations, entomologists in the Mid-South (Angus Catchot – Mississippi State University) have suggested egg thresholds broken-down by trait package:

WideStrike Cotton: Treat on 10-15% egg lays on bloom tags

BG2 cotton: Treat on 25-30% egg lay on bloom tags.

These thresholds are supported by observations made across the Southeast last year, including in North Carolina and Virginia, that worms have a higher chance of surviving on blooms than on any other part of the plant. These thresholds have not been established through experimentation and I consider them to be extra protective. Budworm eggs are identical to bollworm eggs and this species is controlled by Bt toxins. I have seen both budworm and bollworm moths in cotton this year.

Some growers have planted conventional cotton this year. We have established egg and larval thresholds in Virginia for non-Bt varities:

Eggs: 10 eggs per 100 terminals or 2 eggs per 100 fruiting forms (most cotton we have scouted has reached this threshold)

Larvae: 3 live worms per 100 terminals or 3% damage to squares, blooms, bolls

Currently, we have experienced no unexpected injury to Widestrike III or TwinLink technologies. I would not assume these varieties to be bulletproof in a high pressure year, but I do think that these technologies offer good protection in our area.

I recommend spending the extra money on a worm-specific product instead of relying on pyrethroids. Vial tests in Suffolk have indicated a trend towards resistance for several years and there have been field failures reported south of us this season. Besiege and Prevathon are good choices because they offer residual control. Besiege targets sucking-bug pests in addition to worms. I have had inquiries about Intrepid Edge. Virginia Tech has not tested this product in cotton. It has performed well in soybean tests and in cotton tests in other regions (Jeremy Greene- Clemson University, South Carolina). Keep in mind that no product works well against large larvae. Due to the early nature of this year’s flight, we may experience additional pressure later this season. I will keep you updated on what’s happening in Virginia. Please call if you have anything to report.

Sally 919-801-5366

 

What You’ll See in the Field at the Virginia Ag Expo

As another reminder, the Virginia Ag Expo is Thursday, Aug. 3 at Renwood Farms in Charles City.  The event opens at 7:30 am and will run through mid-afternoon.

There is something for all corn and soybean farmers in the field this year.  Go on the field tour and you will be able to chat with Extension Specialists, company reps, and others about the research being conducted or anything else on your mind.

As always, the Ag Expo is home of one of our numerous on-farm corn hybrid and soybean variety tests.  This year, you will view 31 corn hybrids from 11 companies and 47 soybean varieties from 14 companies.  Drs. Mike Flessner and Charlies Cahoon will demonstrate off-site herbicide injury with some of our newest seed/chemical technologies.  Dr. Wade Thomason is evaluating in-furrow and starter fertilizer in corn.  The soil fertility team, led by Dr. Mark Reiter, is investigating fertilizer recommendations to ensure optimum production for high yielding soybeans.  You will view one of Dr. David Holshouser’s seeding rate trials as he is in the process of establishing variable rate seeding recommendations.  You will also see an experiment that you may have viewed at last year’s Ag Expo investigating the interaction of planting date with relative maturities.  Companies are participating in our plots with in-furrow and foliar sprays that offer potential to enhance yield potential under high-yielding conditions.  Finally, you’ll go below ground to view Virginia’s state soil, a Pamunkey loam, and discuss this yield contest-winning properties with NRCS personnel.

This is a walking, go-at-your-own-pace tour designed to fit your interest and schedule.  Buses will be running continuously to take you to and from the plots.  Enjoy!

Insect update for July 20, 2017

This week, our black light trap operators reported a range of zero to 8.5 corn earworm/bollworm moths per night and zero to 2.7 brown marmorated stink bugs per night. The tables are in this pdf file: BLT_20_Jul_2017

The corn earworm/bollworm pyrethroid resistance monitoring program is averaging about 36% moth survival. These are pheromone trap-collected moths from Suffolk, Virginia. The pyrethroid is cypermethrin at 5 micrograms per vial.

Virginia Cooperative Extension ANR Agents, Virginia Tech personnel, interns, and others have started our annual field corn survey for corn earworm/bollworm larvae. It can be an indicator of the pressure that we’ll see in other crops (e.g., soybean) when the moths emerge and fly out of corn fields. We’ll have a full report in the beginning of August (including data from many more counties), but here are the average ear infestations from those surveys already completed (based on sampling 50 ears per field, 5 fields per county): Accomack=29%; Henrico=37%; Southampton=53%; Amelia=18%; Westmoreland=6%.

 

Corn earworm and Fall armyworm trap catch numbers from Virginia sweet corn fields – Week of July 16

Sweet corn farms are being monitored around Virginia for the two most important pests attacking the ears, corn earworm and fall armyworm.  Moth Trap Catch Data are being recorded by:  Katlyn Catron & John Few (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.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

This week we have still not seen the fall armyworm flight yet in VA.  A few moths were caught on the Eastern Shore of VA and a couple other locations, but generally they are not in Virginia yet from their migratory flight from the south each summer.  For corn earworm, trap catch of less than 1 per night means relatively low pest pressure and 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.  Trap catch increased to high levels on several farms this week throughout the state including Northampton Co., Virginia Beach, Page Co., and Montgomery Co.

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 July 16 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 4.4 3
Eastern Shore Accomack ESAREC – woods 1.1 0
Eastern Shore Northampton Bridge Tunnel 33.3 0
Eastern Shore Northampton Capeville 1 1.5 0
Eastern Shore Northampton Cape charles 3.0 NA
Eastern Shore Northampton Eastville 4.5 0
Eastern Shore Northampton Nassawaddox 1.5 0
Virginia Beach Virginia Beach Pungo 1 15.7 0
Piedmont Amelia Field 1 4.0 0.2
Piedmont Hanover Farm 1 3.7 0.0
Piedmont Hanover Haynes 1.1 0.0
Northern Neck Westmoreland Field 1 10.0 0
Northern Neck Westmoreland Field 2 3.7 1
Shenandoah Valley Rappahannock Field 1 5.0 0
Shenandoah Valley Page Field 1 12.0 0
Shenandoah Valley Frederick Farm 1 7.4 0
Shenandoah Valley Frederick Farm 2 3.2 0
Shenandoah Valley Rockingham Farm 1 0.3 0
Shenandoah Valley Rockingham Farm 2 1.0 0
New River Valley Montgomery KC 1.0 0
New River Valley Montgomery KO1 3.3 0
New River Valley Montgomery KO2 9.3 0
New River Valley Montgomery WF1 16.3 NA
New River Valley Montgomery WF2 4.3 NA
New River Valley Montgomery WF3 13.0 NA
New River Valley Montgomery WS1 17.3 NA
New River Valley Montgomery WS2 19.0 NA
New River Valley Montgomery WS3 36.7 NA

Plant Bug Distribution Map

Twenty-three representative cotton fields in eight Virginia counties were scouted weekly for plant bug abundance and square retention. Data for the June 28th through July 13th sampling period is represented in the distribution map below (follow link to view). We will continue to post updates to the map through peak plant bug abundance in cotton. Sweep net and drop cloth samples were taken for each field to account for sampling bias associated with sweep net sampling towards adult captures and drop cloth sampling towards nymphal captures. When sampling cotton fields for plant bugs, look carefully for nymphs (pictured below). Since nymphs are flightless, they may spend more time feeding in an isolated area and cause more damage than adults because their movement in and out of fields is limited. The action threshold for plant bug in Mid-Atlantic cotton is generally eight plant bugs (i.e., adults and nymphs) per 100 sweeps in addition to square retention below 80 percent.

Plant bug nymph feeding on weedy host, buckhorn plantain (Plantago lanceolata).

When viewing the distribution map in full-screen mode, click on the left arrow icon to view map legend. Click on sampling labels on the map to view square retention and number of samples taken from each site. Mean plant bug densities were calculated by sampling four sweet net samples (25 sweeps per sample) and four drop cloth samples across each field. Total adults and nymphs in a single visit were totaled and averaged for each visit within the sampling period.

Click here to view full-screen distribution map

Plant bug distribution map in Virginia cotton sampled from 28 June to 13 July 2017.

Insect report for July 13, 2017

Virginia Cooperative Extension ANR Agents and Virginia Tech faculty/staff have started up their black light traps to monitor corn earworm moths (aka bollworm) and brown marmorated stink bugs for the season. CEW and BMSB catches have been low in the black light traps; however, our pheromone traps in Suffolk, VA are catching moderate numbers of CEW moths–averaging about 5 per night. We tend to pick up more CEW moths in the pheromone than in the black light traps during this time of year. Dr. Taylor’s cypermethrin vial tests are showing about 35% of CEW moths surviving the 5 microgram rate (the moths were collected from the Suffolk pheromone traps). Watson Lawrence reported 26 brown stink bugs in his Chesapeake black light trap this week.