Average nightly corn earworm/bollworm moth black light trap captures for this week were: Dinwiddie=51; Greensville=9; Hanover=3 (first week with more than 0.5 per night); Prince George-Templeton=12; Prince George-Disputanta=3; Southampton=5; Suffolk=17. Here is the Table. At just over 200 vial tests conducted, corn earworm moth survival is 39%.
Virginia Tech Eastern Shore AREC Virtual Field Day
Please find the 2020 Virginia Tech Eastern Shore Agricultural Research and Extension Center Virtual Field Day available via YouTube. Pre-recorded sessions can be viewed in one playlist or you can pick and choose individual topics using the hyperlinks in the attached program.
Playlist link: https://www.youtube.com/playlist?list=PLldHHn24T22mXiFp8Hq9hEn-YPb4gMTM0
The program with clickable links is found by clicking: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/spes/spes-239/SPES-239.pdf
As always, contact us with questions vis email, YouTube comments, or Facebook. Please let us know of any further research or Extension questions that you may have. We hope to see everyone again at our Painter, VA location in person in Summer 2021!
Stay healthy and take care!
Corn earworm report–August 13, 2020
Average nightly corn earworm/bollworm moth black light trap captures for this week were: Dinwiddie = 26; Greensville =4; Prince George-Templeton = 9; Prince George-Disputanta = 6; Southampton = 8; Suffolk = 23. Thanks to our Agents and Growers for their efforts. Here is the data table
Sally Taylor and her entomology program sampled a Cotton Incorporated sponsored planting date experiment today at the Tidewater AREC in Suffolk, VA. We found 2 to 6.5% bollworm-injured bolls in conventional (non-genetically protected against bollworm) cotton. In our Virginia Soybean Board experiment with maturity groups 4 and 5 full-season soybean (beginning pod growth stage), we had 2.3 to 5 corn earworm larvae and up to 3 soybean looper larvae per 15 sweeps.
Leaf-footed bugs are running amuck on vegetables
Over the past couple of weeks our fruiting vegetable crops at Kentland Farm in Whitethorne, Virginia have been invaded by abundant numbers of leaf-footed bugs (Leptoglossus spp.). These bugs that are in the same bug family Coreidae as the squash bug Anasa tristus. They are piercing sucking feeders that have killed entire cucumber and zucchini plants from their feeding on stems and leaves or have caused numerous puncture wounds on fruit, which result in a little fluid oozing from the fruit.
These insect pests can be controlled using the same insecticides that are labeled for use on stink bugs and squash bugs, namely, pyrethroids or neonicotinoids for conventional growers. Organic growers can achieve some suppression of bugs with the use of products containing pyrethrins such as Pyganic or Azera, or with the use of Surround (kaolin clay powder), which also works to prevent sunscald on fruit.
To learn more about this pest, please see the following VCE fact sheet that we produced a decade ago. Wow has it been that long? https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/3012/3012-1522/3012-1522_pdf.pdf
Corn earworm moth catch in the Blacksburg, VA area for Week ending Aug 14
Since early July, we have been monitoring Heliothis traps baited with corn earworm pheromone at on 4 hemp fields and one sweet corn field in and around Montgomery, Co., Virginia. Below are the trap catch results. After a week or two of low catch, the moth activity has picked up especially at the Wall sweet corn.
Corn earworm moths per trap per week
| Week ending | Tru Harvest hemp 1 – Christiansburg, VA | Tru Harvest hemp 2 – Christiansburg, VA | Urban Hort Center – Hemp Blacksburg, VA | Wall Farm – sweet corn Blacksburg, VA | Homefield Farm – hemp Whitethorne, VA | Catawba hemp – Catawba, VA |
| 17-Jul | 2 | 0 | 0 | 61 | 0 | 4 |
| 24-Jul | 5 | 4 | 0 | 49 | 0 | 0 |
| 31-Jul | 0 | 0 | 0 | 9 | 1 | 4 |
| 7-Aug | 8 | 13 | 0 | 30 | NA | 0 |
| 14-Aug | 7 | 4 | 5 | 188 | 18 | 3 |
Corn earworm update for August 6, 2020
Average nightly moth captures for this week were: Greensville =10; Prince George-Templeton = 3; Prince George-Disputanta = 7; Suffolk = 21. Here is the data table
Corn earworm update for July 30, 2020
Black light trap nightly averages for corn earworm/bollworm moths this week in Virginia were: Greensville = 35.6; Prince George-Templeton = 1.0; Prince George-Disputanta = 3.3; Southampton = 2.0; Suffolk = 17.1 (all reports were higher than last week). Thanks to our Agents for their reports.
Resistance monitoring of corn earworm/bollworm using adult vial tests now has 50% of moths surviving the 24-hour exposure to the pyrethroid, cypermethrin at the 5 microgram/vial rate (76 vials tested to date, collected from Suffolk).
Spider mites in many crop fields
Observations from the field this week indicate that there are spider mite infestations at some level in most, if not all, peanut, cotton, and soybean fields in the drought-stressed Virginia regions. Drying of corn and weeds is contributing to this problem. Let’s all hope we get the rain we need to make a good crop this season. Rainy, humid weather will favor fugus that kills mites, but its effect may be mitigated by extremely hot conditions. Just in case, and since our last bad mite year was 2011, see below for a refresh about spider mites and how to treat them in each crop…
Soybean
Concentrate on the field borders and look for the early signs of white stippling at the bases of the leaves. Do not confuse mite damage with dry weather injury, mineral deficiencies, and herbicide injury. Mite infestations will have some pattern, usually originating from field margins. Consider applying a miticide if more than 50 percent of the plants show stippling, yellowing, or defoliation over more than one-third of the leaves. Recommended products include Zeal and Agri-mek (other abamectin products are available, but not labeled for soybean). Lorsban and dimethoate are labeled and may require a second application. Bifenthrin will offer some suppression, but mite infestations will come back stronger.
Peanut
Heavy infestations usually occur first around the borders of peanut fields; then they spread inward throughout the fields. Avoid harvesting spider mite infested cornfields or mowing weedy areas next to peanut fields until peanuts are harvested. Spider mites will readily move into peanuts when corn dries down or is harvested. Be prepared to treat peanuts if adjacent corn is infested. Use adequate pressure and GPA to ensure penetration of the canopy. Comite is our only registered product that works. See graph below from Dr. Mark Abney at UGA.
Cotton
Mite damage first appears as a slight yellowing of the leaves, which later changes to a purplish or bronze color and is usually associated with webbing. Damage occurs especially in spots or on field edges but widespread defoliation is not uncommon if favorable conditions persist. I recommend abamectin (10 oz/A rate is usually sufficient) or Zeal for control. Bifenthrin, other pyrethoids, and especially acephate, will flair mites. If you are treating for plant bugs, I recommend Transform at 2-2.25 oz/A until wetter conditions prevail. Be mindful of the bollworm flight next week and do not make automatic sprays for worms until you confirm a problem in your field. Worm specific products (Prevathon, Intrepid Edge, Blackhawk) are better options than broad-spectrum insecticides (pyrethroids).
Our annual post-bloom survey starts next week. If you need help learning how to scout insect pests, call or text me on my mobile (919) 801-5366.
Corn earworm moth report for July 23, 2020
Prior to this week, corn earworm/bollworm moth counts have been low in southeast Virginia black light traps. For this week (July 17-23), average nightly catches of moths were: Greensville = 7.4; Prince George-Templeton = 0.3; Prince George-Disputanta = 0.7; Southampton = 1.5; Suffolk = 7.4. Thanks to the Virginia Cooperative Extension Agents who are operating traps this season.
We have tested 47 corn earworm/bollworm moths since June 23, 2020 in our pyrethroid resistance monitoring program. Moths are captured in pheromone traps and are exposed to 5 micrograms of cypermethrin inside a glass vial for 24 hours, then rated as dead/down/alive. Untreated controls (in acetone-only treated vials) are also evaluated to correct for control mortality. The average for the past month is 43% moth survival. High survival rates indicate an increased chance of pyrethroid control issues and the need to consider alternative chemistries if a spray is needed.
In a non-Bt corn experiment planted on April 9 at our research farm in Suffolk, VA, we had large corn earworm larvae in the ears last week. Now they have exited the ears and are pupating in the soil. It takes about 10 days for the moths to emerge–this flight out of corn is the one that we are concerned with in crops such as soybean, cotton, peanuts, and vegetables–the moths want to lay eggs on a good food source for their larvae. Please check back with the Advisory for more pest updates and recommendations.
Virginia Ag Expo Canceled to COVID-19 Concerns
The 2020 VA Ag Expo has been cancelled. The Ag Expo committee with guidance from the Virginia Soybean Association and Virginia Grain Growers Association have made this difficult decision to ensure the health and safety of exhibitors and guests as a result of the COVID-19 pandemic. We will be reaching out to each exhibitor and sponsor to discuss our next steps. We appreciate your support and look forward to 2021!