We are fortunate to have added several new black light traps in the past few weeks, including ones in Surry County (Glenn Slade), Isle of Wight (Janet Spencer), and Virginia Beach-West Neck (Roy Flanagan). Moth counts averaged from 3 to 26 per night this past week; please see the attached table (pdf file) for more details. Additional information: blacklight-table-12-pdf

Resistance monitoring results for this week in Suffolk (based on 222 vials tested) indicated 30.1% of corn earworm moths surviving the 24-hour exposure period to cypermethrin. This brings the seasonal average to 38.2% survival (1,586 vials tested). The 2011 and 2012 line graphs are attached as a pdf. Additional information: cew-cypermethrin-2yr-pdf

The pyrethroid vial tests are still showing high levels of corn earworm survivorship. Thursday, Sean Malone will post the line graph including this week’s vial test totals, but as of now, we are still getting about 45% survivors. This is important to consider when selecting insecticides for ‘worm’ control in soybean fields. We are now beginning to see corn earworms feeding on young pods in some fields. In others, we are not finding any, or just a few. Each field is a separate case and each should be sampled to determine if earworms are present in numbers that warrant treatment. You can find earworms in many peanut fields, but as stated earlier—if you want to treat them, consider it to be recreational, not economic.

We have been sampling sorghum heads for worms this week in four different locations and all but one have levels worm levels that exceed the 1 worm/head threshold. Some samples reached 30-55 per 10 heads, way over threshold. Products labeled for worm control in sorghum are limited (at least all we could find) to Baythroid, Karate/Warrior, Lannate, Mustang Max or Blackhawk (the new Tracer). Of those, Lannate will give the quickest kill but has essentially no residual activity. But, residual activity should not be an issue. If worms are killed, heads will be matured beyond attractiveness before any additional worm infestations would occur. The pyrethroids should also do pretty well, unless pyrethroid resistance becomes an issue in sorghum and we are not sure about that. If spraying sorghum, only the heads need to be treated, not the foliage, so use a sprayer configuration/gallons/pressure that directs as much spray as possible to the heads. That is where the ‘action’ is.

Brown marmorated stink bug populations are still very slow to develop across the state, at least as best we can determine. Since last week, we have added three new counties where low numbers have been found in soybeans: Essex, Appomattox, and Louisa Counties. We are tracking these to see if treatments may be needed. Like last year, we are going to recommend and strongly encourage field edge treatments.

Kudzu bug encounters have slowed and we have added only one of two new counties, Suffolk for one. We are still only finding low numbers of adults and no eggs or nymphs. Hopefully we will not experience any outbreaks.

BMSB nightly black light trap catches are provided in the attached table. Petersburg recorded high numbers again this week. Additional information: bmsb-blacklight-table-12-pdf

Please see the attached table for average corn earworm moth nightly black light trap catches. Additional information: blacklight-table-12-pdf

As Dr. Herbert mentioned in his Aug. 1 advisory, the percentage of corn earworm moths surviving the adult pyrethroid vial tests exceeded 50% last week and is at 44% this week. Attached are the 2011 and 2012 graphs in pdf format. Additional information: cew-cypermethrin-2yr-pdf

SOYBEANS
Many soybean fields are being treated for ‘loopers’ this year. There are worms in fields, but most are green cloverworms with a few yellowstriped armyworms, soybean loopers and even a few beet armyworms mixed in. Folks are seeing more leaf feeding than they are used to seeing and with the high bean prices, are pulling the spray trigger. My opinion is that in a great majority of cases, these sprays are not going to pay any benefits. Soybeans can stand a lot of leaf feeding, up to 30-40% up until blooming and 20% or so after bloom. People only ‘see’ the top leaves where most of the leaf feeding is occurring and are not inspecting the whole plant, so are greatly overestimating the problem. We recommend pulling a few plants and estimating the TOTAL leaf loss considering ALL the leaves on the plant. If you do this easy exercise, you may find that a field that looks bad may only have 5% to 10% actual defoliation.

If a field has been treated, the best advice now is to be sure to scout that field beginning about a week after the spray. Those treatments will have eliminated the beneficial insects so any corn earworm eggs laid after that time will have a near perfect hatch rate. That is, any treated fields are now at much higher risk for earworm outbreaks when pods start forming—and based on the diversity in corn field maturities, we are expecting LONG moth flight for at least 2 to 3 more weeks.

There are areas on the Eastern Shore that are experiencing high levels of beet armyworm in soybeans and we are hearing of a few in this area of the state. But the same principles apply. Treat beet armyworm as just one of the many possible leaf feeders and only spray if defoliation levels reach the recommended percentages.

KUDZU BUGS
As of this week, we have found adult kudzu bugs in soybean fields in 14 counties (Amelia, Brunswick, Dinwiddie, Greensville, Halifax, Henry, Isle of Wight, Lunenburg, Mecklenburg, Nottoway, Patrick, Pittsylvania, Southampton, and Sussex). My guess is that fields in many more counties are infested but we just have not had the time to check more. That will change. We have just added two more (three total) very competent field scouts to focus on mid-central and upper central counties. To date, no kudzu bug eggs or nymphs have been found. The folks to the south tell us that it is just a matter of time before we do. We will keep providing updates.

UPDATE ON CORN EARWORM PYRETHROID VIALS
Last week an average of 50% of corn earworm moths tested survived the pyrethroid treated vial exposure. So far this week, the rate has dropped a little to 44% (53 dead of 120 tested). More will be tested this week for next weeks report.

PEANUTS
A mix of corn earworms and a few beet armyworms are now showing up in peanut fields. Most or our peanut fields have A LOT of leaf canopy and can withstand A LOT of worm feeding before treatments will pay. Thresholds are set at 4 worms (corn earworm, beet armyworm, or fall armyworm) per foot of row. Few fields will actually reach these high levels. Many more will be treated with no real benefit.

COTTON
We are seeing more fields this week at the ‘old’ bollworm egg threshold which would trigger sprays on any conventional cotton not protected with Bollgard2 or Widestrike. BG2 and WS fields could benefit from a treatment by next week, at least according to what we have learned over the past several years of field research. If a field does not get infested with bollworms, and we do find some each year, be sure to keep checking for stink bug damage until the 7th or 8th week of bloom. Most fields are still in the most critical stink bug feeding weeks (3rd, 4th and 5th weeks of bloom) so need to be protected if internal boll damage exceeds 10% to new bolls. If bollworm sprays include a high pyrethroid rate, they will be also protect against stink bugs.

We had a high BMSB report from Petersburg this week, capturing nearly 20 BMSB per night in their black light trap. This trap is in a prime location for detecting brown marmorated stink bug, being within 100 feet from woods with tree of heaven at the edge, and next to an organic area with lots of weeds. Other reporting stations had zero to 2.5 BMSB per night. Please see the acknowledgments in my corn earworm moth trap report, they also apply to the BMSB reports; and please see the attached table for more trap catch details. Additional information: bmsb-blacklight-table-12-pdf

Corn earworm moth catches were generally low this week, ranging from zero to 6.5 moths per night in area black light traps. Please see the attached table for more details. Thanks to the following for their reports: Laura Maxey (King William), Helene Doughty (Virginia Beach/Hampton Roads AREC), Roy Flanagan (Virginia Beach/West Neck), Mary Beahm (Warsaw/Eastern Virginia AREC), Mark Kraemer (Petersburg), Ames Herbert and crew (Suffolk/Tidewater AREC), Chris Drake (Southampton), and Keith Balderson (Essex). Additional information: blacklight-table-12-pdf