The big question today is where are the kudzu bugs we expected to see in our soybean crop? As of this week, we have not seen any adults or nymphs in the early planted full season crop. In fact, the same situation is being reported for much of the eastern US. Dominic Reisig at NCSU says that even in NC, the only reported infestations are from southernmost counties. Last summer by this time we were seeing many full season early planted files with infestations of adults that have moved from adjacent overwintering sites. The only bugs we have found so far have been in kudzu patches. So, what’s the difference in years and why the delayed movement of adults? All we can say is that it must be related to the colder than normal temperatures we experienced during the winter. We know that in the Suffolk area there were at least two nights when temperatures dropped below zero (æF), and of course it was even colder north and west of us. Could those cold temperatures have killed some of the overwintering adults reducing the overall population levels? We do know from our adult overwintering emergence traps that were placed throughout much of the state that adults survived and emerged this April and May in about 12 counties in the southern part of the state. Why they did not move into early planted soybean fields is another unanswered question. From what I can gather from reading and talking with other entomologists in the southeast, 2014 is shaping up to be similar to 2011 when the first generation of kudzu bugs developed in kudzu (mostly) and other alternate hosts and only the second generation moved into soybean fields. This certainly seems to be what is happening this year. In some ways this scenario, if it plays out, will simplify the field scouting and threshold determination. The original kudzu bug threshold developed in the southeast was based on this second generation that moved into reproductive stage (flowering early pod) soybean fields and it is based on number of nymphs (see below). We have initiated our 2014 soybean insect pest survey so will be reporting updates as they come in so stay tuned. Treatment Thresholds for 2nd Generation Kudzu Bugs, Nymphs Present Sweep Net ” An average of 1 nymph/sweep, 15/15 sweeps ” Take at least ten 15-sweep samples to represent the entire field ” Sampling should not be biased by sampling close to field edges where populations may by congregated Canopy Observation ” At least 10 observation spots representing the entire field ” Nymphs easily found on main stems, leaf petioles or leaves.

Please see the attached short note and state map showing the 13 counties where kudzu bug traps have caught emerging (from overwintering) adult kudzu bugs. Looks like we are set up for an interesting summer. Ames Herbert Additional information: kudzu-bug-methods-results-docx

The Virginia distribution maps for these two invasive species are attached (please click “More”). Additional information: sep5distributionmaps-pdf

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

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

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

Please click “More” to view the August 5, 2013 versions of the brown marmorated stink bug and kudzu bug distribution maps for Virginia. Additional information: bmsb-kb-8-aug-2013-pdf