Corn earworm is on the rise. Trap catches started increasing this week, up from near zero last week, and we are seeing moths flying in soybean, peanut and cotton fields. The worst news on corn earworm relates to the resistance monitoring program. As in the past several years, we are testing live-caught male moths in what we call the AVT program (adult vial test). Live moths are placed individually into small glass vials pretreated with a known amount of cypermethrin (the pyrethroid used throughout the south in the AVT program). We check the vials in 24 hours and any live moths are considered to be ‘survivors’ demonstrating resistance. Although we have only tested 363 moths to date, we found that 48% survived in this week’s sample (see the attached chart). This is the highest level ever recorded in Virginia. Last year we found about 40% survivorship in some later season samples, which was the highest level for the years up to 2009. We will continue posting the AVT results, but all indications are that we may be in for some pyrethroid control issues again this summer. Additional information: cew-avt-jul-22-2010-ppt
Category Archives: Commodity
Cotton insect update: stink bugs low, bollworm increasing
So far we are not seeing much boll damage from stinkbugs. We think this is due to the overall very hot, dry weather we are experiencing. Week before last I saw 106 degrees on a local bank billboard in my hometown (Franklin, VA), the first time ever according to the ‘old-timers’. This week Johnny Parker with Commonwealth Gin reported that he looked at a couple of thousand acres and found only about 3 bolls total with stink bug damage. He says he has never seen stink bug pressure this low. Yesterday he found a hot spot in an irrigated field approaching 10% boll damage with about 15% dirty blooms. The only insect in the field was tarnished plant bug so he assumed they had caused the boll damage (spots with light internal damage).
Corn earworm/bollworm is on the rise. Trap catches started increasing this week, up from near zero last week, and we are seeing moths flying in soybean, peanut and cotton fields. Stan Winslow with Tidewater Agronomic, Inc. in North Carolina reported today that they were finding an increasing number of bollworm eggs in cotton. We are recommending that growers not react to eggs, but wait to see how they progress and base any sprays on worm escapes. If worm pressure gets high, we can expect some escapes. For example, last year we found 2-4% boll damage on some Bollgard 2 and Widestrike varieties. But time will tell. We may or may not have to treat depending on how many worms break through the Bt and Widestrike toxins.
Insect trap counts on the Eastern Shore for Week Ending July 16
Blacklight trap catch in Painter this week again yielded very little activty from the major moth pest species. Weekly counts were as follows: 0 European corn borer, 0 armyworm moths, 2 corn earworm, 6 hornworm moths (increasing), 42 green stink bugs (increasing), 3 brown stink bugs (decreasing). We are still not seeing the main flight of corn earworm. Spider mites remain an important pest concern particularly in areas that have missed the rain, or commercial tomatoes. An outbreak of fall armyworm in late-planted corn was also reported this week. Coragen insecticide is a new option for fall armyworm control in early whorl stage corn. It has shown very good efficacy, with a long residual, and it is a safe chemical to apply.
Corn earworm black light trap captures for the week ending 15 July 2010
New supplemental label for Belay applied aerially on soybeans, cotton, and potatoes
Attached is a Belay Supplemental label that has been approved by the EPA and is pending state approval. This Supplemental Label allows Belay to be applied aerially in soybeans, cotton, and potatoes. In addition, the aerial use rate is 3 to 6 fl oz/A. This is a higher use rate than the current ground application label (3 to 4 fl oz/A); however, the EPA has approved the change of the use rate for Belay when applied by ground in soybeans and cotton. That Supplemental Label will be out this coming week. Additional information: belaysuppl-label-aerialappl-2010-bel-0015-xcaflny-pdf
Insect pest activity on the Eastern Shore for week ending July 8
Blacklight trap catch in Painter has revelealed very little insect activty this week. We are still not seeing the main flight of corn earworm, which is good news for our growers because we they’ve had enough to worry about with drought. The hot dry weather has caused some outbreaks of Spider mites in tomatoes and soybeans. Commercial tomato growers are having particular difficulties managing this pest even with some of the best miticide tools on the market for vegetables (Oberon, Portal, Acramite, and Agrimek). I’ve heard of some tomato fields receiving applications of all of these products on a 5 day rotation and they still have spider mites, particularly in the lower canopy. Some rain could really help.
Introducing – Insect trap counts for Virginia Beach
Click more to find the pheromone trap counts and blacklight trap counts for corn earworm moths, beet armyworm moths and some other pests in Virginia Beach. In 2010 we initiated a monitoring program for these pests at the Hampton Roads AREC and on three commercial farms near Pungo, VA. These data will be posted weekly so that you can monitor the flights of these key insect pests of vegetables and field crops.
In summary corn earworm moths have been flying in the Pungo, VA area since June, but we’ve probably not seen the huge migratory flight that occurs each year around mid July. Beet armyworm moths have yet to appear in traps. Additional information: vabeach-pheromone-trapping-2010-xls
Cotton insect pest update
Not much is happening in cotton right now in terms of insect pests. The hot, dry weather seems to have things on hold, for the most part. Spider mites are common on a lot of field edges but are not widespread. We are not seeing much evidence of square loss to plant bugs (in untreated fields) and square retention is in the 90% + range. A few stink bugs, mostly brown stink bugs, are beginning to show up and soon we will begin assessing bolls for stink bug damage using our newly released ‘Decision aid for stink bug thresholds in Southeast cotton’ which presents a dynamic internal stink bug damage percentage threshold (changes as the crop matures) that begins with 50% internal damage in the first week of bloom. We will post more details soon.
Corn earworm update
It is too early to say a lot about corn earworm, but year in and year out, this critter causes us a lot of problems. Each year we conduct a large survey of field corn in late July to get a ‘read’ on the size of the population that could move to soybean, cotton, peanut and other host crops. Although we have not done the survey, some random checks of sweet corn and field corn show from 40% to 90% infested ears. This constitutes a possible threat. Earworms are worse in dry years as fewer are killed by rain (can drown pupae before they mature, can wash eggs from plants, can increase the incidence on fungal worm diseases, etc.). The other ‘shoe to drop’ is the issue with pyrethroid resistance. In the last two years (2008 and 2009) we found a large increase in the number of moths that survived in our pyrethroid vial testing program (from less than 5-10% survivors prior to 2008, to 20-40% survivors in 2008 and 2009). So far this year we have tested a total of 235 moths from May 27 to the present. The % survivorship has fluctuated, as is normal, starting at 13%, then to 12%, to 7%, to 25% in last week’s sample. Granted these results are from a small number of moths, but all indications are that we may need to address use of pyrethroids again this summer. We will keep posting the information.
General crop insect pest overview
Because of this continuing hot, dry weather, we are not seeing a lot of insect activity in cotton, peanuts or soybeans. There are a few exceptions. Grasshoppers are doing some damage to soybeans in certain areas. Spider mites are starting to show up in most crops, but so far, the buildup is pretty gradual. Finally, there is some hope this Saturday for some decent amounts of rainfall for a lot of the area. If we miss that opportunity&& Potato leafhoppers are showing up in peanuts, but again, the buildup is gradual. We are just beginning to get a picture of how the 2010 corn earworm population is developing. We may be in for some problems (see the Corn earworm update), again, if the weather doesn’t turn around with more frequent rains. PS, if we could shoot about ½ million deer we would solve a lot of our ‘pest’ problems, at least for many of our soybean growers.