Many full-season soybean crops on the Eastern Shore of Virginia were sprayed for insect pests this week. In many cases, these sprays were needed as pest numbers of spider mites, corn earworms, green cloverworms and other caterpillar pests were high. In the fields that I insected, I saw a lot of green cloverworm, corn earworm, yellowstriped armyworm, and some beet armyworms. I did not see soybean loopers, which often are hard to kill. Beet armyworms have also shown resistance to pyrethroids in past trials on the Eastern Shore. A number of different insecticides were applied. Some growers sprayed Steward to combat the complex of caterpillars; whereas some others sprayed Orthene and a pyrethroid such as Warrior to combat the mix of pests. Other growers sprayed a generic Lorsban 4E, which provided efficacy against the spider mites as well as the caterpillar pests including beet armyworms. Let’s hope our growers do not have to spray again, as these sprays were applied early in the crop, and we’ve still probably yet to see the major flight of corn earworms that attack the pods.
Category Archives: Insect
Eastern Shore insect trap catches for Week ending Aug 6
Click More to receive the insect trap catches for the Eastern shore of Virginia for the week ending August 6. In summary, we are seeing an increase in trap catch of corn earworm and beet armyworm moths at most locations. Green stink bug catch also increased in black light traps. Additional information: es-insect-trap-counts-7-30-10-8-6-10-xls
Corn earworm outbreaks early and heavy in some fields, not in others
Corn earworm has moved into soybean fields across much of Virginia. This is earlier than normal and most are faced with the decision to treat (or nor) flowering stage beans. Infestation levels vary a lot from field to field from almost no worms in lush canopy fields, to drought stressed open canopy fields with as many as 25+ per 15 sweeps. Although we have decent thresholds for foliage feeding and pod feeding, there is little guidance as to the impact of flower feeding by corn earworms. Several years ago researchers in North Carolina (Eckel et al. 1992) concluded that flower feeding contributed to yield reductions by delaying pod set, but no exact thresholds were developed. Without good guidelines as to how many can be tolerated, we are suggesting that low to moderate numbers (6 or less medium plus large worms/15 sweeps) could be safe, especially if beans are growing well with good soil moisture. More than that may represent a threat. Again, just a ‘grab’.
We are also getting a lot of calls from folks finding live worms after pyrethroid sprays, in cotton, peanut and soybean fields. Most are using either Karate Z or Baythroid XL and the ‘misses’ are about equal among the products. The most obvious cases are where there were very high numbers of worms so the survivors are still quite noticeable. We visited one field that had been sprayed 24 hours earlier and found an average of about 4 to 8 worms/15 sweeps. Since it was still not forming pods, I suggested that it not be retreated, yet.
Of course, any field that has been treated will be very susceptible to any subsequent infestations, as beneficial insects would have been mostly eliminated so be sure to begin re-scouting 7 days after the last application. If another treatment is needed, strongly consider a non-pyrethroid.
We are also seeing a mix of worm species including yellow striped armyworms, green cloverworms, and maybe some tobacco budworms. Corn earworm is still the primary species, so I would direct the spray program to those.
Bollworm thresholds in conventional cotton
We are finding threshold levels of bollworms (eggs and live worms) in conventional cotton (no Bollgard2 or Widestrike). Those fields should be managed using the old system (treat at egg threshold and retreat in 5-7 days). The best approach for Bollgard2 and Widestrike cotton is the treat one time 5-7 days after the egg threshold, which targets any escaped worms. Not treating Bollgard2 or Widestrike cotton could be a mistake. For the past 2 years, we have seen as much as 2-3% boll damage in some Bollgard2 varieties, and as much as 10% damage in one Phytogen variety. A single pyrethroid application (highest labeled rate) cleaned up the problem. One cautionary note, we have gotten reports of worms escaping pyrethroid treatments in cotton.
EPA Federal Register on Cancellation of Pencap-M insecticide
Pesticide Federal Register Items for the Week of July 12-16, 2010
>
>Methyl Parathion: Cancellation Order for Certain Pesticide
>Registrations Date of publication: July 16, 2010
>Citation: Volume 75, Number 136, Page 41482-41483
>http://edocket.access.gpo.gov/2010/2010-17404.htm
>Purpose: This notice announces EPA’s order for the cancellations,
>voluntarily requested by the registrants and accepted by the Agency, of
>products containing methyl parathion, pursuant to section 6(f)(1) of
>the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as
>amended. This cancellation order follows an April 28, 2010 Federal
>Register Notice of Receipt of Requests from the registrants listed in
>Table 2 of Unit II. to voluntarily cancel all these product
>registrations. These are the last products containing this pesticide
>registered for use in the United States. In the April 28, 2010 notice,
>EPA indicated that it would issue an order implementing the
>cancellations, unless the Agency received substantive comments within
>the 30 day comment period that would merit its further review of these
>requests, or unless the registrants withdrew their requests. The
>Agency received comments on the notice but none merited its further
>review of the requests. Further, the registrants did not withdraw
>their requests. Accordingly, EPA hereby issues in this notice a
>cancellation order granting the requested cancellations. Any
>distribution, sale, or use of the products subject to this cancellation
>order is permitted only in accordance with the terms of this order,
>including any existing stocks provisions.
>Chemical(s): Methyl Parathion**
>Comments: EPA has established a docket for this action under docket
>identification number EPA-HQ-OPP-2009-0332. The cancellations are
>effective July 16, 2010.
>Contact: Kelly Ballard, Pesticide Re-evaluation Division (7508P),
>Office of Pesticide Programs, telephone number: (703) 305-8126; fax
>number: (703) 305-5290; e-mail address: ballard.kelly@epa.gov.
>
>
>Methyl Parathion; Registration Review Proposed Decision; Notice of
>Availability Date of publication: July 16, 2010
>Citation: Volume 75, Number 136, Page 41484-41485
>http://edocket.access.gpo.gov/2010/2010-17403.htm
>Purpose: This notice announces the availability of EPA’s proposed
>registration review decision for the pesticide methyl parathion and
>opens a public comment period on the proposed decision.
>Registration review is EPA’s periodic review of pesticide registrations
>to ensure that each pesticide continues to satisfy the statutory
>standard for registration, that is, that the pesticide can perform its
>intended function without unreasonable adverse effects on human health
>or the environment. Through this program, EPA is ensuring that each
>pesticide’s registration is based on current scientific and other
>knowledge, including its effects on human health and the environment.
>Chemical(s): Methyl Parathion
>Comments: Submit your comments, identified by docket identification
>number EPA-HQ-OPP-2009-0332. Comments must be received on or before
>September 14, 2010.
>Contact: Kelly Ballard, Chemical Review Manager, Pesticide
>Re-evaluation Division (7508P), Office of Pesticide Programs, telephone
>number: (703) 305-8126; fax number: (703) 305-5290; e-mail address:
>ballard.kelly@epa.gov.
>
>Mailing address for all listed staff: Office of Pesticide Programs,
>Environmental Protection Agency, 1200 Pennsylvania Ave., NW,
>Washington, DC 20460
Eastern Shore Insect Trap Counts for Week ending July 29
This week the corn ear worm flight seems to have spread throughout both counties with all trap locations showing increased activity. This week also showed a jump in beet armyworm catches at both the Eastville and Painter locations while cornborer activity has shown a significant decrease. Click more to view a spreadsheet of pheromone trap catch and blacklight trap catch from various locations on the Eastern Shore. Additional information: es-insect-trap-counts-7-16-10-7-23-10-5-xls
Black light trap captures for the week ending 29 July 2010
Black light trap captures of corn earworm moths greatly increased for nearly all of our reporting stations. The lowest nightly average was recorded in Petersburg (4) and our highest included Richmond County (69) and Prince George County (76). Please refer to the attached Table for more nightly averages. Additional information: blacklight-table-10-pdf
Corn earworm survey and predictions
Annually, we conduct a survey to estimate corn earworm infestation levels in field corn in late July. Earworms develop in corn, then move to other crops such as soybean, cotton, and peanut in August. We determined the number of corn earworms found in 50 ears of corn from 5 randomly selected corn fields in each of 24 counties, totaling 5,800 ears and 116 fields sampled. Statewide, 42% of ears were infested with earworms. This is up from 36% in 2009. Regional averages were 12% infested in Northern, 28% in the Northern Neck, 39% in Mid-Eastern, 58% in the Southeast, and 46% on the Eastern Shore. See the attachment with results from each county and many more details. From the survey, it looks like the areas of greatest risk to heavy infestations of earworms are the southeastern ‘cotton/peanut’ counties, and the Eastern Shore. However, as large as this effort is, it is not a complete picture. We always recommend scouting individual fields to determine exactly what is happening in terms of corn earworm as well as other pests and crop problems. We will continue posting moth catch numbers and other information regarding the 2010 insect pest situation.
Additional information: cew-survey-table10-2-docx
Corn earworm pyrethroid resistance update
As of July 29, we have tested a total of 768 corn earworm moths in our pyrethroid AVT (adult vial testing) program. Although the percent survivorship is down somewhat from last week, we are still seeing greater than 20% survive (see the attached line graph). Could this mean that field failures are likely? Possibly, especially if worm populations are large. Our goal is to process as many moths as we can and post these weekly updates. We are also responding to calls from crop consultants, advisors and growers. We have one reported case of a ‘less than acceptable’ level of control in a peanut field. Could some of those surviving worms have been tobacco budworms, which are known to be more difficult to control with pyrethroids? Possibly, but it is almost impossible to distinguish between corn earworm and tobacco budworm without inspecting the moth parts of the worms under magnification in lab. We do know that budworms can be in the mix, up to 30% one year when we did a lot of worm IDs. Bottom line, this is the third consecutive year that local corn earworm populations are demonstrating high levels of pyrethroid resistance. Proceed with caution and consider non-pyrethroids especially in peanut or soybean fields with a lot of worms.
Additional information: cew-avt-jul-29-2010-ppt
Eastern Shore Insect Trap Counts for Week Ending July 23
Mr. Kyle Sturgis and Bill Shockley have embarked on a more extensive insect pest trapping effort on the Eastern Shore. Click more to view a spreadsheet of pheromone trap catch and blacklight trap catch from various locations on the Eastern Shore of Virginia. This same spreadsheet will include other locations and will add new catch numbers on a weekly basis. We are getting organized to deliver a more comprehensive picture of the activity of major agricultural pest insects on the Eastern Shore.
In summary the spreadsheet shows the first real rise in counts of both corn earworm and European corn borer in the Mappsville and Assawoman areas of the Eastern Shore. Activity in Eastville appears to be low. There have been no catches of either beet armyworm or fall armyworm so far. It is early for those pests, although a fall armyworm infestation in late planted corn was seen in Northampton County this week.
Additional information: es-insect-trap-counts-7-16-10-7-23-10-xls