Cotton Insect Situation No. 15 August 15, 2002 Blake Layton Extension Cotton Entomology Specialist Area Specialists: Dr. Gordon Andrews Dr. Mike Williams Cotton Insect Hotline: 1-800-445-4931 Last Newsletter for 2002: This will be the last regular issue of the Cotton Insect Situation Newsletter for the 2002 growing season.  However, we will continue to update the Cotton Insect Hotline (1-800-445-4931) at least once weekly through the end of the month.  The Cotton Entomology Web Site, www.MSUcares.com/insects/cotton, also provides a variety of information on cotton insects and their control.  We would welcome any comments or suggestions on how to improve the newsletter for next year.  Please direct these to: Cotton Insect Situation, Box 9775, Mississippi State, MS 39762-9775. Crop Situation: The Weekly Weather and Crop Report for the week ending August 11 showed that 12% of the crop had open bolls, which is only 1% behind the 5-year average for this time period.  Seventy-six percent of the crop was rated ‘good’ to ‘excellent’.  Statewide temperatures ranged from a low of 58o F to a high of 99o, with an average temperature for the week of 81o, which is normal for this time of the year.  Note that this is an average of 21 DD60s per day.  Statewide rainfall averaged 0.14 inches below normal. Insect Situation: All species of late season insect pests are present in numbers high enough to potentially cause problems on late-maturing fields.  This makes it difficult to concentrate on any single species.  Armyworms and loopers are more common than usual this year.  Intrepid is one of the most cost effective treatments for armyworms and loopers, but keep in mind that the relatively low rates used for these caterpillars are not effective against bollworms and budworms.  Aphids are building in some fields, but late season aphids rarely require treatment because they are almost always controlled by a resurgence of the Neozygites fungal disease.  Stink bug numbers continue to be low in most fields, but their numbers will likely increase as soybeans mature.  When making late treatment decisions the first factor to consider is crop maturity.  Some fields have already reached the point where they are no longer susceptible to insects.  Also, keep in mind that, for most pests, thresholds can be increased once the crop enters cutout.  However, there is also the reality that insect populations are often at their highest from now until the end of the season.  It’s a race to the finish line, between the crop and the insects. Mississippi Entomological Association Annual Meeting: Mark your calendar! The annual meeting of the MEA will be held on October 28, 29, and 30 2002 in the Bost Extension Building at Mississippi State University.  Actually the educational portion of the meeting does not begin until the morning of the 29th, but the annual golf tournament will be on the afternoon of the 28th.  The meeting will begin early on the morning of October 29 and continue until noon on the 30th.  The annual MSU Entomology Alumni Supper will be on the evening of October 29.  This meeting provides an opportunity to hear the latest information on Mississippi insect problems.  For more information about the MEA meeting call the MSU Department of Entomology (662-325-2085). How Safe is our Food?  The May 2002 issue of National Geographic devotes 50 pages to this question, including a 20-page article on transgenics. . The other 30 pages are devoted to microbial contamination in food and there is little mention of pesticides.  The article on transgenics includes pictures of Monarch butterfly larvae that have died from eating pollen from Bt corn and a photo of a protestor dressed as “Monsatan”.  It also mentions the reduction in insecticide use that has occurred in cotton as a result of Bt-cotton and discusses other benefits of transgenics.  Overall, the article provides an even-handed presentation of the issues surrounding transgenic crops, and most folks who work in agriculture, and especially in crop protection, will enjoy reading this article.  No, you probably can’t buy a May issue of National Geographic at the newsstand now, but you can find one at your local library Boll Weevil Eradication Update: This year the Boll Weevil Eradication Program is running approximately 325,000 traps on around 1.15 million acres of cotton.  During the week of August 1 through 7 a total of 1811 boll weevils were captured and 82,769 acres were treated with ULV malathion.  So far this year, a total of 34,211 boll weevils have been captured in the state (that’s about 30 weevils for every 1000 acres) and a cumulative total of 725,220 acres have been treated.  Approximately 76% of the cotton fields in the state, or 84% of the acres, have been totally free of boll weevils through August 7 of this year.  There aren’t than many boll weevils left in the state, but there are more than we were hoping to see at this point in the program.  The heavy rainfall experienced in late August and September of last year, combined with the ‘no-fly period’ and the mild winter definitely delayed Mississippi’s boll weevil eradication effort.  Still, the end is in sight and the days of the boll weevil in Mississippi are numbered.  Because boll weevil activity and movement traditionally intensifies in late August and September, the period from now until the end of the season is a very critical one for Mississippi’s BWEP.  All scouts should be alert for live boll weevils and/or boll weevil egg-laying punctures. Any detection of live weevils or egg-laying punctures (either in squares or small bolls) should be reported to Boll Weevil Eradication Personnel immediately.  Telephone numbers for the various BWEP work units are listed in the following table.    Boll Weevil Eradication Program Work Unit Offices Region Office Phone Number Officer in Charge 4 Aberdeen (662) 651-4820 Arlon Cox 3 Taylor (662) 983-2666 Mark Ferguson 3 Kosciusko 1-800-400-3321 Charles Rogillio 3 Bolton (601) 605-2709 Danny Meyers 2 Rolling Fork 1-877-788-9444 Mike Mullendore 1B Cleveland 1-800-297-1680 Doris Sprouse 1A Inverness 1-800-269-9930 W. G. Griffin 1A Marks 1-800-997-9914 James Burgess How Late Can One Set a Pickable Boll?  The Node above white bloom = 5 + 350 DD60s concept is a useful tool for determining when insecticide treatments can be terminated on crops that have cutout in a timely manner due to boll load or have cutout prematurely due to environmental stress, but what about late maturing crops?  What about a crop that does not reach cutout in time to mature these last bolls before frost or before the target defoliation date?  How late can one set and mature a pickable boll, and how long does one need to protect such a crop from insects?  The answer to these questions depends on where in the state the crop is located and how late one is willing to wait before defoliating.  Once these two factors are established, one can then examine the probability of being able to accumulate enough DD60s to mature a white bloom that occurs on a given date. The three graphs included in this issue show the probability of accumulating enough heat units (750 DD60s) to mature bolls that appeared as white blooms by a specific date at either Holly Springs, Stoneville, or Jackson.  These graphs were produced by Dr. Gordon Andrews based on 28+ years of historical weather data for each location.  Note that 5 lines appear on each graph.  The 'earliest' line represents a targeted defoliation date of September 20, while the 'latest' line is for the average graph date of first freeze for the area. The following table summarizes some of the key points of information that are included in these graphs. Latest Date When a White Bloom has an 80% or 50% Probability of Accumulating 750 DD60s          Location    80% Probability by October 1    50% Probability by First Frost       Holly Springs          August 2         August 11          Stoneville         August 12         August 26           Jackson         August 15         August 28       Adapted from graphs provided by Dr. Gordon Andrews As for when to terminate treatments for budworm and bollworm on "late" crops, the last population of effective bolls still needs to be protected from damaging populations until they have accumulated 350 to 400 DD60s. That's 18 to 20 days at an average of 20 DD60s per day.  This means that some of these late crops could still require protection until after Labor Day.  Another Plant Bug Trial: The table below presents the results of a second tarnished plant bug efficacy trial that was recently completed in Sunflower County.  The plots were treated on August 5, using a CO2 powered backpack sprayer calibrated to deliver 9.5 gallons of finished spray per acre.  Treatments were evaluated at three and seven days after treatment.  Thanks again to Mr. Richard Horne and Lee Simmons for helping establish this trial. Small Plot Tarnished Plant Bug Efficacy Trial 2, Sunflower County, 2002 Treatment Lbs. Ai. Per acre Avg. No. TPB per 100 plants * 3 DAT 7 DAT Adults Nymphs Adults Nymphs Orthene 97SP 0.5 5 bc 14 cd 8 bc 11 b Orthene 97SP 1.0 13 ab 9 cd 5 c 7 b Trimax 4SC 0.047 7 bc 37 ab 14 b 18 ab Centric 40WG 0.05 7 bc 5 d 9 bc 5 b Danitol 2.4EC 0.2 4 c 26 bc 10 bc 5 b Capture 2EC 0.06 4 c 19 cd 8 bc 8 b Untreated -- 19 a 52 a 30 a 27 a * Numbers within a column that are followed by the same letter are not significantly different (P > 0.1). Cotton Entomology Web Site Table of Contents: Following is a list of the table of contents for the Cotton Entomology Web Site, which can be reached through: www.MSUcares.com/insects/cotton. Current Situation Overview of Cotton Insect Management in Mississippi Cotton Insect Control Guide Insect Scouting and Management in Bt-Transgenic Cotton Cotton Insect Identification - Pictures of Cotton Insects Cotton Insect Situation Newsletter (Historical Archive of Back Issues) Annual Summaries of Mississippi's Cotton Insect Season (Historical Archive) Cotton Insect Sampling Methods Annual Cotton Insect Losses and Control Costs Recent Papers on Cotton Insects in Mississippi Northeast Counties - Mike Williams: The major problem with NE Mississippi cotton at this time is that it needs a rain.  The weatherman has promised and by the time this is read maybe we will have a good soaking for the area.  Insect problems remain fairly steady.  We have seen some treatable populations of bollworms in the area this year, but the bollworm moth flight seems to be slowly dwindling.  Tobacco budworm has increased slightly, necessitating the treatment of conventional cotton with materials other than pyrethroids.    We have also begun to find an occasional fall armyworm in cotton.  These critters will be seen as small caterpillars under boll and square bracts causing window-paning of the bracts then they are fairly easily found at 3 to 4th instar in blooms, but move back down to bolls where they puncture from the bottom of the boll and destroy it.  Unlike bollworms/budworms, larger FAW usually will `hole-up’ in one boll.   Beet armyworms are still seen in the area, but not in high numbers.  Watch for `hits’ from these critters. We have also had some questions about recurring aphid populations – once the fungus comes the populations may come back, but the fungus will knock them back in a day or so.  There are also some reports of building whiteflies.  If the population begins to build in a field especially where cotton is young, applications may be warranted. Stink bugs are also a major concern, though after seeing high numbers of them early, anticipated  high populations have not developed.  Clouded plant bugs and tarnished plant bugs are also potential  pests which are building in late maturing cotton.  It has been another neat year and potential is there for us to harvest a good crop.  I have enjoyed getting to work with many of you in 2002 and look forward to continued association.  The removal of the boll weevil has lessened the intensity of insect management and enabled us to more easily manage crop pests.  Thank you for your support. Trap reports for week ending August 14, 2002          County Boll weevils Bollworms Budworms BAW no. per 33 traps no. per trap/week no. per trap/week no. per trap/week Coahoma   27.5 4.0 13.5 Tunica 0.0 29.0 7.0 23.5 Bolivar 0.0 14.3 3.0 7.3 Washington   1.0 0.0 1.0 Madison   18.0 9.0 38.0 Yazoo 0.0 29.0 24.5 60.0 Humphreys   148.0 44.5 125.5 Leflore   102.0 45.0 140.0 Carroll 1.4 25.0 24.0 14.0 Grenada 0.0 43.0 5.0 19.0

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