Cotton Insect Newsletter Vol. 20, No. 2, May 29, 2002 Call 1-877-629-1474 for Cotton Insect Hotline

Cotton Situation:  Planting is nearly complete, with the exception of a few thousand acres that might still be planted after wheat.  If we don't get some rain, there will be very little additional planting.  Temperatures that have finally warmed up to the 60's in the evening and mid-to-upper 80's in the afternoon, are providing some decent growing conditions.   We planted a late thrips test nine days ago, and it came up to a pretty good stand.  Now if I can just get some thrips to find it.  Some of the most advanced cotton will now be starting to square, but the majority of fields still have some growing to do before the plants begin squaring.  This could be a good thing if the moisture conditions start to improve (as we all hope they will).  Insect Situation:  Overall, thrips are causing the most problems again this week.  Some farmers are trying to decide whether or not to treat some older cotton with five or more true leaves.  In my experience, treating older cotton plants to control thrips has never provided much return on investment.  I realize the plants can get very ragged looking, and terminals may be severely damaged.  But these plants have been exposed to unusually cool temperatures, and in most cases, low soil moisture conditions in addition to thrips infestations.  Warm days and some much needed shower activity can revitalize such cotton plants.  After a few days of rapid growth, thrips will fall by the wayside.  When you see new leaves that have no thrips damage, the infestation has probably run its course.  Also keep in mind that even when insecticides applications are properly timed at exactly the right rates, there is no guarantee of getting a yield response from controlling thrips.    Now there are plenty of cotton fields where thrips may be causing problems on cotyledon to 3-leaf stage cotton plants.  In such situations, you have a much better chance of getting a return on your insecticide investment, and in all likelihood, one application will suffice.  I don't know how many of you have tried seed treatments for thrips control, but where we have looked at these in research plots, they have not performed adequately in cotton planted during a period from the last week in April to about May 10.   In cotton planted April 29 this year, plants with seed treatments alone didn't fair much better than the untreated ones.  Where we applied Orthene 97 PE as a foliar spray when plants were from cotyledon to first true leaf stages, we saw good control.   The 6-oz rate was used, but I have also heard of some good results at 3 oz/acre.   Keep in mind that these appear to be primarily western flower thrips, as do most of the thrips that have been observed in farmers’ cotton fields in the Pee Dee area.  Tobacco thrips are often a problem, but their numbers appear to be way down this year in cotton.   Beet armyworms are showing up in several fields now.  We have seen armyworms in May before in South Carolina, but it is unusual to see them in economically important numbers.  There have been a few fields sprayed.  One field in Sumter County was sprayed with a low rate of Tracer, and the worms were cleaned up.   I haven't heard of any bollworms or tobacco budworms in cotton yet, but there appears to be more budworm activity in tobacco than last year.  Bollworms are not attracted much to tobacco, however, they will often be found on whorl-stage corn and wild host plants this time of year.   My summer workers are putting up pheromone traps now for both beet armyworms and fall armyworms.  These are the green, universal-type traps.  You will also be seeing some of the wire-cone traps that are baited with pheromone lures to attract moths.  It would be nice if I could say that the traps will cut down on infestations in nearby cotton fields; unfortunately, this does not happen.  Only the male moths are attracted to the pheromone and there are usually plenty of them left to take care of the females.  Pheromone traps do give us some indications of when peak numbers of females will be attracted to cotton fields to lay their eggs.  Also we need to collect bollworm and budworm moths to conduct vial tests for pyrethroid resistance.   Cotton Insect Information:  As I mentioned last week, the newest edition of “Cotton Insect Management,” IC-97, is now available at your County Extension Offices.  You can get the latest insecticide recommendations here, as well as at  http://cufan.clemson.edu/pestmgmtguide/ on the Clemson Web.   The “Cotton Insect Hotline” is now up and running.  You may access messages concerning current cotton insect problems by dialing 1/877-629-1474.  New messages will be recorded on Tuesday and Friday mornings.  If you have information concerning some insect situation in your area, you can leave a message.  All you have to do is follow the instructions at the end of my Hotline message.  This is a great way to get important insect information to me, so I can spread it around.  Cotton Scouting Schools:  Let me remind you again that two Scouting Schools will be held, one at the PDREC on June 5 and the other at Orangeburg-Calhoun Technical College (room 1512, in the auditorium nearest the hospital) on June 6.  There will be a $10 fee, payable at registration between 8:00 and 9:00 AM.  Credits for CCA’s and private-pesticide applicator certification will be presented to those in attendance.       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