Cotton Insect Newsletter Vol. 21, No. 15, August 27, 2003 Call 1-877-629-1474 for Cotton Insect Hotline

Last Newsletter:  This will be the last regularly scheduled “Cotton Insect Newsletter.”  Those of you that are on the listserver to receive “Cotton Insect Blurbs” will continue to get those reports.  I will also continue the “Cotton Insect Hotline” for another week or so. Cotton Situation:  Wow, this season has gone by too fast!  Seems like we just planted this crop and it will soon be time to harvest.  A few bolls are starting to open and more and more fields are blooming-out-the-top.  Now is the time to make some judgment calls on fields that may no longer need protection from insect pests.  It all depends upon the amount of fruit on the plants that still need protection.  There won't be much point in protecting squares, since there is insufficient time remaining for even a large square to produce an open boll that might be harvested.  Insect Situations:  Mike Sullivan told me that he was seeing some increase in bollworm activity in the Savannah Valley with egg counts running up to 20/100 in some fields.  Most of the fields here at the Pee Dee REC are pretty well past being susceptible to this latest flush of bollworms, but I know there were quite a few fields planted in June that are still mighty green.  Expect to see some increased pressure in late-maturing cotton during the next several days. Stink bugs are strange critters.  We worked hard to pull stink bugs into cotton plots by inter-planting Group IV soybeans (which built up a sizable population of brown stink bugs).  When we plowed the soybeans down a couple of weeks ago, we expected that the cotton would be the logical place for the stink bugs to go.  Guess again.  When we looked at boll damage yesterday, there was actually less damage than 3 weeks earlier.  Where did the stink bugs go?  Mike Sullivan said they were seeing lots of fields with damaged bolls, but couldn't find the stink bugs.    We don't seem to know much about when and why stink bugs move, but they do seem to have a propensity to travel.  It's also not a given that a particular cotton field is going to be hit by stink bugs.  There are plenty of fields that will not be damaged.  That's why we still recommend looking at damage on quarter-sized bolls.  You may not be able to find the bugs but you will know when damage becomes unacceptable and an insecticide application is needed.   Even if you can't find the pests that did the damage, the materials recommended for stink-bug control should also take out other pests that might feed inside bolls such as tarnished plant bugs.                      There have been some reports of soybean loopers hitting cotton fields below the lakes.  These insects will typically start feeding on leaves in the lower parts of the plants, working their way up the plants.  Our threshold says to control loopers when there has been 25% defoliation and bolls are still developing.  In cotton that is nearing maturity, the bottom defoliation induced by loopers may actually be beneficial in allowing increased air movement which will mitigate the harmful effects caused by organisms that produce boll rot.  Bt-cotton will take care of cabbage loopers, but it is not very effective on soybean loopers.  Tracer, Steward, Intrepid and Denim will all provide decent control of loopers.   Boll Weevil:  Boll weevils will be on the move as cotton plants start to cut out.  If you know of any fields that do not have pheromone traps up, please call Randal Lynch or Wyman Taylor at 1/800-269-9928. Cotton Field Days:  The Fall Field Day will be held at the Edisto REC on September 4 with registration at 9:00 AM.  A peanut tour will begin at 10:00 and run until noon.  At about 1:45, the cotton and soybean portion of the program will begin with some field tours and end about 3:45.   At the Pee Dee REC at Florence, there will be a Cotton Field Day on September 11.  A morning program will begin with registration at 8:00 AM.  An afternoon program will continue at the Delta & Pineland Company, Hartsville Research Station, Hartsville, SC.  Meet there at 2:15.   Lunches will be provided at Florence and at Blackville.  The programs will include lots of opportunities to observe field research on some of the following topics: cotton varieties, fertility, fungicides, nematode resistance, plant growth regulators, stink bug control, thrips control, bollworm control, herbicides systems and harvest-aids.      Mitchell Roof  Extension Entomologist

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