Cotton Insect Newsletter Vol. 19, No. 8, July 5, 2001 Call 1-877-629-1474 for Cotton Insect Hotline

Hotline:  I'm using the “Cotton Insect Hotline” now to supply you with timely information on the cotton-insect situation.  The recorded messages are updated on Tuesday and Friday morning.  This service is sponsored by the South Carolina Cotton Board.  The toll-free number is always displayed in the upper right-hand corner on the front page of every Newsletter.  Cotton Situation:  Cotton planted by the first week in May should be blooming this week, however,  much of the state's cotton didn't get planted until later.  In fact, there is a sizeable acreage of cotton containing plants that haven't started squaring yet.  On Tuesday, I saw some fields with plants in the 2-leaf growth stage, and many of the field in the same area had not begun squaring.  Sometimes it becomes a little confusing for scouts when they have cotton blooming in a several fields and cotton just beginning to square in others.  For example, estimating square retention rates is important in cotton during the first 2-3 weeks of squaring, but such estimates would have little importance after cotton begins to bloom.  There is a tendency to just forget about square retention once you see blooms in a few fields.  But remember this - - plant bugs can be more detrimental in late-planted cotton because the plants are running out of time to square - bloom - and set bolls.  Therefore, continue to monitor square retention in late-planted cotton fields.  Cotton plants should be setting 90% or more of squares.  If percentages are lower, insects such as plant bugs may be causing problems. Insect Situation:  Problems have been few and cotton insect pest have been scarce this week.  We didn't hear much at all from the tobacco budworm.  Eggs were almost nonexistent in most cotton fields.  I just heard a few reports of small worms in conventional cotton, but don't know of anyone that sprayed for them.  The next round will begin about July 10 in the Savannah Valley according to my crystal ball.  I'll warn you though, it hasn't been working too well lately.  I have observed that large corn earworms have begun to crawl out of corn ears and into the ground, where they will stay for 10-12 days before becoming moths.  The moths will crawl out of the ground, assuming that the tunnel isn't full of water, in which case they would have to do the back stroke.  Although the percentages of infested corn ears seemed to be fairly low in the Pee Dee area, I suspect there will still be enough bollworm moths to supply most cotton fields with eggs.  I'm in a bit of a quandary these days.  I need bollworm (and budworm) moths to run vial tests for pyrethroid and Tracer resistance.  I need bollworms to send to Starkville, MS for Bt-resistance tests.  We use our pheromone traps to try and catch the moths we need, but during the last couple of years, the numbers just haven't been there.  Mike Sullivan is apparently having the same problem in the Savannah Valley this year, although the numbers will probably increase there shortly.  Well, if we don't catch any moths, I guess we won't have to worry much about resistance development. Stink bugs are showing up now in cotton that has begun to bloom and set bolls.  That means it is time to start scouting for stink bugs and damage.  Examine 25 to 50 quarter-sized bolls in each field.   Randomly select bolls from different areas of the field, selecting bolls purely on the basis of size.  Do not pull bolls on the basis of external markings.  Sometimes the black spots will correlate with stink bug damage and sometimes they won't, but if you pick only those that appear to be damaged, you will probably overestimate the severity of an infestation.  We recommend an insecticide treatment when you find 15% of the bolls with stink-bug damage.  When I find damage, I want to look for some stink bugs in a field to make sure that it is indeed a stink-bug problem.  I always carry a plastic pan (about about 10" x 12" x 5" deep) in my truck that I purchased somewhere like Wal Mart.   To check for stink bugs, I just walk along a row of cotton holding the open side of the pan close to the plants.  I stop every 3 or 4 feet and beat the plants twice against the pan to dislodge and capture the stink bugs.  More than likely you will find green or southern green stink bugs which are killed fairly well by pyrethroids.  But, if you see mostly browns, Bidrin would be a much better choice of chemical.   See Cotton Insect Management IC-97 or access http://cufan.clemson.edu/pestmgmtguide/ on the internet for recommendations for the control of stink bugs and other insect pests. Aphids are showing up in a number of fields throughout the state.  In most cases, there will be a few plants that are heavily infested, and few if any aphids will be found on the majority of plants.  Hopefully, the fungus Neozygites fresenii will soon begin to bring them down.  Phil Roberts has reported the fungus showing up in aphids in Southwest Georgia already, so it shouldn't be long.  I made some collections on July 3 and FedExed them to the University of Arkansas for diagnosis the same day.   When I hear something about the fungus, I will let you know on the Hotline or the Cotton Listserver.  Notoxus spp., hooded beetles, are some of the most abundant insects in cotton fields at the present time.  They probably kill a few aphids and eat a few eggs of other insect pests, so they are certainly not causing any problems.  If you view a hooded beetle (about 1/8" in length) under magnification, you will see a projection from the pronotum extending over the head; thus, the name, hooded beetle.   Mitchell Roof  Extension Entomologist

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