The Virginia distribution maps for these two invasive species are attached (please click “More”). Additional information: sep5distributionmaps-pdf
Category Archives: Pest Group
Black light trap counts for week ending August 29, 2013
Please click “More” for the corn earworm moth and brown marmorated stink bug tables. Corn earworm moth numbers varied greatly by location, with some very high captures in Charles City. Brown marmorated stink bug numbers ranged from zero to 2.4 per night. Thanks to the following for their reports this week: David Moore, John Allison, Laura Maxey, Mary Beahm, Keith Balderson, Scott Reiter, Kelvin Wells, Mark Kraemer, Ames Herbert and crew, and Helene Doughty. Additional information: blt29aug13-pdf
Black light trap catches for week ending Aug. 22, 2013
Please click “More” to view the average nightly black light trap captures of corn earworm moths and brown marmorated stink bugs (BMSB). This week’s corn earworm catches ranged from 0.1 to 5.1 per night; BMSB ranged from zero to 1.9 per night. Thanks to our trap operators Chris Drake, Keith Balderson, Mary Beahm, Mark Kraemer, Mike Parrish, Ames Herbert and crew, Laura Maxey, and Jim Jenrette for their reports this week. Also, thanks to all those providing a location and power source for these traps. Additional information: blt-aug22-pdf
Pyrethroid resistance monitoring update–Aug. 22, 2013
As of August 22, 2013, we have evaluated 545 Helicoverpa zea moths (=corn earworm) (=bollworm) in our cypermethrin vial tests (cypermethrin is a standard pyrethroid). Results are provided in the attached pdf document (please click “More”). In the vial test, moths are exposed to cypermethrin for 24 hours and are then rated as dead, down, or alive. For the entire season to date, an average of 22% of H. zea moths have survived the test. Please refer to Dr. Herbert’s August 13th advisory for how to best interpret these vial test results. Additional information: cypermethrin-pdf
Brown marmorated stink bug (BMSB) survey in cotton (so far, none found)
Kudzu bug distribution in Virginia–Aug. 22 update
Please click “More” to view the Aug. 22, 2013 distribution map of kudzu bug in Virginia soybean and other hosts. Also in the attachment is the percent control of a long list of insecticides for kudzu bug (courtesy of Jeremy Greene at University of Georgia and Phillip Roberts at Clemson University). If you are at kudzu bug threshold (1 nymph per sweep) and decide to treat your field, you may want to consider a product (or one with similar active ingredients) from the list that has a high percent control. When choosing a product, please keep in mind any other pests that are present in your field. And, please read and follow the label. Additional information: kudzu-bug-distribution-va-2013-pdf
Brown marmorated stink bug (BMSB) update for soybean
Please click “”More”” to view the most recent update on BMSB distribution in Virginia soybean (please see slide 1 of the attached pdf document). On August 20, our soybean scout Ed Seymore reported that in the last week stink bugs have started to move out of corn and into soybean fields in the counties of Culpeper, Fauquier, Franklin, King George, Rappahannock, Rockingham, Spotsylvania and Stafford. These counties have reached the threshold for stink bugs of 5 stink bugs in 15 sweeps (in the fields that we scouted). Attention should be paid to fields that border corn and woods especially with the tree of heaven (end report from Mr. Seymore). Note that thresholds in soybean do not distinguish between BMSB and native green and brown stink bug species (also shown on slide 1). Dr. Herbert’’s insecticide efficacy trials and on-farm edge treatment research suggest that most insecticides provide initial stink bug knock down (please refer to slides 2 and 3 for efficacy trial results, where the higher percent control, the better). Residual activity varies, and reinvasion can occur after loss of residual protection. Since BMSB exhibit a strong soybean field edge preference, perimeter-only treatments may be effective. Please remember to always base management decisions on proper scouting and thresholds, and always read and follow the pesticide label (sometimes, products and/or rates that we include in our tests are experimental; also, product labels and rates may change from year to year). Additional information: bmsb-pdf
Black light trap catches for week ending Aug. 15, 2013
Please click “More” for this week’s black light trap catches of corn earworm moths and brown marmorated stink bugs. Thanks to all of our trap operators for their reports! Additional information: blt-15-aug-2013-pdf
Soybean aphids spotted in Essex County Virginia: Refresher on Thresholds and Sampling
I just got a report of a soybean aphid infestation in Essex County. It has been several years since we have seen soybean aphid in Virginia, but the summer conditions (generally cooler, overcast) favor development of that pest. Reports of spotty infestations are also coming in from other states, North Carolina included.
As a reminder, the current economic threshold for aphids is an average of 250 aphids per plant, on two consecutive field visits spaced about 5-7 days apart (hit the ‘more’ button for more). This is because aphid populations can ‘crash’ quickly due to heavy pressure by natural enemies like lady beetles, parasitic wasps, and fungal diseases. When scouting, choose a ‘Z’ or ‘W’ shaped pattern to cover the entire field and sample at last 20 to 30 plants per field by examining the entire plant including stems and upper and lower leaf surfaces. Use the aphid/plant average for determining the need for treatment. The threshold applies to soybean through the R5 growth stage (3 mm long seed in the pod at one of the four uppermost nodes on the main stem), after which time plants can tolerate 1,000+ aphids with no threat to yield.
Additional information: soybean-aphid-threshold-ppt
Corn earworm activity is increasing, and, an update on the pyrethroid resistance monitoring results
CEW moth activity is definitely beginning to increase. We are now catching 20-30 per night in our traps compared to 4 or 5 per night last week. We are not sure how this will progress. A lot will depend on the weather, and eventually, corn harvest. We will keep posting updates.
PEANUTS: We are beginning to find just a few worms in peanut fields—way below any reasonable threshold (See the advisory I posted on the peanut/worm situation for more details).
SORGHUM: A few worms are beginning to show up in sorghum heads (See the advisory I posted on sorghum head worms).
SOYBEAN: We are getting reports of a few worms in soybean fields but not at threshold levels, and not threatening the seed.
COTTON: Although we have found a few CEW eggs, we are finding almost no worms. This could be year when the BG2 and WideStrike provide enough protection, without additional foliar sprays.
PYRETHROID RESISTANCE: Keep in mind that I use the term ‘resistance’ loosely. We cannot prove/disprove actual resistance using the AVT (Adult Vial Testing) method, only determine the percent that survive the pyrethroid challenge. So, where do we stand this year? If you open the file (‘more’ button) you can get a quick comparison of where we are compared to last year—so far we are seeing only about 30% survivorship. But also notice that the number of moths tested to date is very low, which could bias our results. Is 30% survivorship enough to warrant a shift to a non-pyrethroid—my answer is, it depends. My rule of thumb is—if a field is at or just above the threshold (check that for each crop), a pyrethroid applied at the highest labeled rate, using a spray system that achieves good plant coverage, will do well. But, if a field is 3 to 4 times the threshold, or higher, a non-pyrethroid will be needed.
Additional information: cew-avt-results-aug-13-pptx