Cotton Insect Newsletter Vol. 19, No. 9, July 11, 2001 Call 1-877-629-1474 for Cotton Insect Hotline

Cotton Situation:  We have received some fairly decent rainfall during the last 3 to 4 weeks.  It looks like farmers are going to make one of the best corn crops in the last 20 years.  Cotton is growing well and prospects look good, but there is still a long way to go.  The July 9 issue of the South Carolina Weekly Weather and Crop Bulletin estimated that only 56% of the crop had begun squaring (the 5-year average is 74%) and 13% had set bolls in comparison to 20% in 2000 and the 5-year average of 20%.  This crop-growth information will lag somewhat behind the actual field situation as it takes a while to gather the information from County Agents, but it does point out that this crop is a little behind on the developmental curve.  If you want to see some really late cotton plants, there are some fields planted behind wheat in Lee County that are barely in the two-leaf stage. Cotton planted between April 15 and May 1 is setting bolls rapidly now.  In some plots at the PDREC designated for bollworm control research, the plants are already at 5-6 nodes above white bloom.  Insect Situation:  Our bollworm pheromone traps were checked Monday and Tuesday, and there were very few moths in the Pee Dee area.  Very few eggs and only an occasional damaged square were found in scouting our research plots.  Egg counts have not increased much in the Savannah Valley area as of this writing. I have been going to a few Red-Wolves baseball games this year.  Last Saturday night and the Saturday before, there were absolutely no moths circling the lights.  I can't remember ever seeing so few moths attending baseball games, and there haven't been many crossing the highways at night.   What does all this mean?  Obviously, the corn earworm moths haven't left the corn fields yet, at least not in this area.  When will they be leaving?  There should be moths coming out of corn fields at any time in the Savannah Valley and they won't be far behind in the Pee Dee area.  Development of corn earworms will be at least a week later in most of the Piedmont counties. I don't know yet how many acres of Bt-cotton were planted in SC.  Last year we had about 75%, and from what I have heard, it could be somewhat less this year.  Bollworms usually don't cause any problems in Bt-cotton until after plants begin to bloom.  Eggs laid on and around blooms and bloom tags appear to have the greatest chance of producing bollworms that will end up in small bolls.   Scouts should be checking whole plants for eggs and small worms in Bt-cotton that has begun blooming.  When 75 eggs and/or 30 small worms (less than 1/4" long) are found, an insecticide treatment should be applied to prevent economic damage.  Another bollworm threshold is directed toward applying a rescue treatment to cotton when large worms have become established.  In addition to the cursory examination of whole plants, scouts should look closely at a white bloom, a pink bloom, and two small bolls on each plant examined for larvae and damage.  An insecticide treatment is recommended when scouts report 5% damaged bolls and/or 3 large worms (more than 1/4" long).  Other Insect Pests:  There is not too much happening in terms of other insect pests this week.  Aphid numbers are increasing, and so are the beneficial organisms.  Last week, I collected some aphids in a cotton field at Cades in Williamsburg County which had a moderate infestation level.   When the aphids were examined at the University of Arkansas, 10% were infected with the fungus Neozygites fresenii.  We also had 4% of aphids infected in a field at the PDREC.  When I collected aphids at Cades yesterday, the infestation was somewhat more intense, but it appeared that 50-60% of the aphids had already died from the disease.  I collected from a Lee-County field last week where the disease was not found and there were no visual signs of the disease yesterday.  Results from this week's survey will appear on the Cotton Insect Hotline and the Cotton Listserver. Stink bugs are showing up in somewhat higher numbers this week.  Scouts should be looking at quarter-sized bolls to assess damage. Boll Weevil Containment:  I spoke with Randy Lynch this morning to see how the trapping program was progressing.  He indicated that pheromone traps appear to be up on all fields as of today.  There are probably some fields that have not yet been discovered for one reason or another.  For example, one large grower has planted about two times the amount of cotton submitted as intended acreage.  Most of these “unintended” fields have been located, but there are probably some that have not.  If you see a cotton field without traps, whether it belongs to you or someone else, please report it to the proper authorities by calling 1-800-269-9928.  “False Mealy Bugs”:  This is my nickname for a beneficial insect that is showing up in somewhat greater numbers than usual.  These insects will be found in association with aphids, as they do like to eat them.  They aren't mealy bugs, but are instead the nymphs of small, dark-brown lady beetles of the genus Scymnus.  The white, waxy covering can be scraped away to reveal the small nymphs that are shaped similarly to their larger cousins.   Mitchell Roof  Extension Entomologist

This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. Brand names of pesticides are given as a convenience and are neither an endorsement nor guarantee of the product nor a suggestion that similar products are not effective. Use pesticides only according to the directions on the label. Follow all directions, precautions and restrictions that are listed. The Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, sex, religion, national origin, disability, political beliefs, sexual orientation, marital or family status and is an equal opportunity employer.  Clemson University Cooperating with U.S. Department of Agriculture and South Carolina Counties.  Issued in Furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of May 8 and June 30, 1914.  Public Service Activities