Cotton Insect Newsletter Vol. 19, No. 2, May 23, 2001

Cotton Insect Hotline:  Some of the earlier-planted cotton is now in the 4- to 6-leaf stage of growth or somewhat more advanced where they have received a little rain or were able to irrigate.  For the most part, however, rain showers have been few and far between and growers are waiting on a good rain so they can either plant or get some seed sprouted.  I would guess that we are about 85-90% planted at this stage, and following the first decent rain, the remainder of this crop will be planted in short order.  Above the lakes, most growers are through planting, but there may be a bit more yet to plant below the lakes. We used to say cotton planted after May 15 was mighty risky.  Back when we had boll weevils to worry about, it was common practice to begin planting at least by April 15.  Now the odds seem to favor late-planted cotton and there have been some years that such cotton actually provided higher yields than the early-planted cotton.  In light of the successes that I have seen during the last several years, I wouldn't be afraid to plant late.  There even seem to be some advantages from the insect control standpoint.  You don't need much for thrips control and you often avoid getting hammered by the first bollworm flight.  Stink bugs might be a bit worse, but that's not always the case. Insect Situation:Thrips are the most prevalent insect pests in most cotton fields, as would be expected for this time of year.  Dry soils have prevented the natural uptake of soil insecticide in some fields, and thrips may be causing more damage than growers would like to see.  In many cases, one or two foliar insecticide treatments may be needed to prevent economic damage.  Temik is considered to be a systemic insecticide, since the active ingredient is translocated from the roots to the leaves and terminals.  When Temik is dropped in the furrow at planting, the granules will be scattered below the seeds.  When rainfall occurs, water percolates through the soil particles and removes the aldicarb (or its derivatives) from the gypsum or corn cob granules, thereby transporting the material deeper in the soil where it will be more available for uptake by the developing root system.  Unfortunately, there has not been sufficient moisture for the process to occur here at the PDREC or most other places.  You certainly wouldn't expect to see much thrips control under these conditions, but my thrips control plots that were planted on May 1 had little damage where Temik was applied.  What about thrips control in cotton planted the last week in May or early June?  Small grains have completely dried out, as have roadside grasses and many other plants that serve as hosts for thrips.  Much of the thrips movement from these plants to cotton should have already occurred, so I would not expect to see great numbers of thrips attacking cotton that will be emerging during the next couple of  weeks.  In response to a couple of questions that I received this week concerning seed treatments, they should provide adequate thrips control for this late-planted cotton.  Compared to Temik, seed treatments will provide protection for a shorter period of time, they will be somewhat less efficacious, and they will not kill nematodes.  But if you are just looking for thrips protection on late-planted cotton, then Gaucho, Adage or even an Orthene seed treatment would probably do the job.  I'm getting a few calls about grasshoppers in no-till and  minimum tillage situations.  There are a number of products that can be used to control grasshoppers.  Most of the pyrethroid insecticides will do the job.  Sevin, Lorsban, methyl parathion  and malathion are some of the other products that will control grasshoppers.  The key is to avoid treating until you have a problem.  We don't have a threshold to give you on this one, but when you see grasshoppers damaging plants in an area of a field, you may need to treat that area.  In many situations you can get by with spraying a few rows, or perhaps even treating grasshoppers in fence rows, water ways, etc. before they get a shot at your cotton plants.  Just remember, the bigger they are; the harder they fall (and the more they will eat).  The grasshopper nymphs start hatching from egg cases below the ground in May and, in some cases, will proceed until the end of July.  As they grow, of course, they will produce more damage.  There are naturally occurring microbes that often control hoppers; fungi seem to be the best source of killer infections.  If we get into a wetter environment soon, as we all hope and pray, diseases may provide some assistance.  Fortunately, the species that are economic pest of crops in this area will only produce one generation per year.  I understand that armyworms have been a problem in a few cotton fields that bordered fields of small grains.  After the small grains dried out, the armyworms moved into the next available greenery and started chewing.  Apparently, only a few rows of cotton had to be treated in most of these situations. Boll Weevil Program:  I talked with Randal Lynch this morning and he indicated that they were in the process of mapping fields and would probably be done with that during the next 10 days.  They will begin setting up traps on June 15.  Scout Schools:  Cotton Scouting Schools will be held at Orangeburg-Calhoun Technical College (Building C, room 118) on June 5 and at the PDREC near Florence on June 6.  Register between 8:00 and 9:00 A.M.   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