We have initiated our annual program to assess adult corn earworms (moths) for susceptibility to pyrethroid insecticides. As you may recall, this process has been in place for many years throughout much of the southeast. Adult corn earworms (moths) are captured live and placed individually into small glass vials pretreated with either a pyrethroid insecticide, or untreated as a ‘control’. After 24 hours, vials are inspected to determine the number of dead (susceptible) and alive (resistant) moths. Each year we capture and test as many corn earworm moths as we can manage to track the percent that survive. This survival percentage is at least an indicator of how susceptible corn earworms are to applications of the many pyrethroid insecticide options for growers.
We are already seeing some alarming results. First, our moth captures are very high for this early in the season. As of this week (May 23-27), we have already captured and tested over 200 moths, many more than last year at this time. The largest sample was tested mid week and 25% survived. This is a very high early season survival rate compared with previous years and is not a good way to start the season. We will press to capture and test as many corn earworm moths as we can over the next several weeks. Stay tuned to this VA Ag Pest Advisory for weekly updates.
Category Archives: General Comments
Invitation reminder and agenda for the June 2 field tour at the Virginia Tech Tidewater AREC in Suffolk, VA
The Virginia Tech Tidewater Agricultural Research and Extension Center (AREC) will hold an early-season field crops tour during the morning of Thursday, June 2nd, 2011. The tour will be held at the Center’s research farm (1045 Hare Road, Suffolk, VA). Specialists will display field research in progress and present information for the 2011 crop season. Topics include disease and insect control in cotton, peanut, wheat, and soybean, weed control in Liberty-Link soybean, and ongoing physiology research in peanut and wheat. Of particular interest will be ongoing work to address regulatory and industry changes resulting in the restricted use or loss of certain crop protection chemicals such as Vapam® and Temik®. Certified crop adviser continuing education credits and pesticide applicator recertification credits (categories 1-A, 1-C, 10, and 60) will be available for participants.
All interested in commercial production of field crops are invited to attend. Arrival is at 8:30 am with the program starting promptly at 9:00 am and running through lunch at 12:30 pm. More information is available through local Virginia Cooperative Extension offices or by contacting the Tidewater Agricultural Research and Extension Center main office at 757-657-6450, ext 402. Please see the attached tour agenda (pdf). If you are a person with a disability and desire any assistive devices, services or other accommodations to participate in this activity, please contact the Tidewater Agricultural Research and Extension Center at 757-657-6450 (TDD number is 800-828-1120) during business hours of 8 am and 4:30 pm to discuss accommodations five days prior to the event.
Additional information: brochure-2011-pdf
Date set for Virginia Tech – Eastern Shore AREC’s Annual Field Day
The Eastern Shore AREC will host its annual field day at their facility in Painter, VA on June 28, 2011. Registration will begin at 8:00 AM with the tour beginning at 9:00 AM. A lunch will be provided at the end of the tour (~12:00 PM). A more specific agenda will be developed soon, but, the tour will include stops on weed management, soil fertility, insect management, water quality, and disease management for vegetable and field crops. Please mark this date on your calendar and we hope that you can join us.
Invitation to the Virginia Tech Tidewater AREC’s Early Summer Row Crops Tour–June 2, 2011 at 9:00 am (at the Hare Road Research Farm)
The Virginia Tech Tidewater Agricultural Research and Extension Center will be hosting their annual ‘Early Summer Row Crops Tour: Insects, Diseases, and Agronomics’ on Thursday, June 2, 2011. The tour will begin at 9:00 am at the Tidewater AREC Research Farm (1045 Hare Road, Suffolk, VA) and lunch will be provided, courtesy of Berry Lewis with Bayer CropScience. Further details will follow. If you are interested in an equipment, company or agency display, please contact Ames Herbert (herbert@vt.edu) as soon as possible. If you are a person with a disability and desire any assistive devices, services or other accommodations to participate in this activity, please contact the Tidewater Agricultural Research and Extension Center at 757-657-6450 (TDD number is 800-828-1120) during business hours of 8 a.m. and 4:30 p.m. to discuss accommodations five days prior to the event.
Fall Armyworm Feeding and Small Grain Regrowth
The following comments were provided by Dr. Wade Thomason, the Virginia Tech Small Grains Specilist.
A number of fields have experienced minor to severe armyworm feeding this fall resulting in almost complete defoliation in some cases. Now the question is how much damage has been done and whether or not the small grain crop should be replanted.
The growing point for the small grains is below the soil surface at this time (and will be until spring) so the crop can tolerate defoliation without damage to the growing point. When the worm feeding ceases, these plants should begin to regrow so replanting should not be necessary. The only case that would be different would be if the worms fed on the same plants again and again, which could ultimately use up the plant root reserves. Finally the tillers we produce in the fall are very important to grain yield and how many tillers we get depends a lot on how many heat units the crop is exposed to. A clipped plant that begins to regrow tomorrow stands to benefit from better fall conditions (warmer temperatures) than a replant situation which would likely take 10 days to emerge.
Late season fall armyworm outbreak
I started getting calls and visits yesterday from homeowners and growers with complaints about ‘worm’ infestations. Fall armyworm is the culprit and apparently the problem is severe and widespread. Fall armyworms are spreading into newly planted fields of oats, rye and other fall grass forages, and into newly seeded home lawns. Calls are coming in mainly from Surry and Isle of Wight Counties, but that could be the result of the attention growers and crop advisors are paying to fields in those areas. One common denominator seems to be that most infested fields are adjacent to pasture or hay fields. Apparently, the worms have been developing in those fields and are now on-the-move into fields with tender newly emerge leaf shoots. Based on the number of reports, I suspect this problem is even more widespread. Emerging wheat and barley fields are certainly also at risk.
Fall armyworm has two ‘strains’ and I suspect this is the ‘grass strain’. I also suspect that this widespread infestation is the result of a huge migratory flight from the south—another in a long line of caterpillar invasions that started with early corn earworm problems back in July. This late season fall armyworm invasion is certainly an unusual problem. I have never seen anything like this in the 22 years I have been working in this area.
Rod Youngman on main campus (he works with insect pests of turf and forages) advised that any of the pyrethroids labeled for forages or small grains should provide good control if applied at the high rate, but should be applied NOW. He believes that seedlings are the most at risk and should be treated ASAP. Fall armyworms are surface plant feeders, so they are pretty vulnerable to pesticides. We also believe that fields grazed off by these worms should spring back once they have cycled out. Their life cycle should put them into to the pupal stage in another week or less. And of course, a good hard frost would take-em-out.
Corn earworm moth black light trap captures for week ending 23 Sep 2010
Corn earworm moth black light trap captures for week ending Sep 16, 2010
In general, corn earworm moth catches were lower than those of the last several weeks. The average number caught per night were as follows: Petersburg (38); Prince George-Wells (2); Prince George-Lipchak (9); Southampton (43); Suffolk (26); Northumberland (9); Warsaw (22). Please see the attachment for more details. Additional information: blacklight-table-10-pdf
Corn earworm moth black light trap captures for week ending 9 Sep 2010
Black light trap captures for week ending 2 Sep. 2010
Please see the attached table for current corn earworm moth catches. Additional information: blacklight-table-10-doc