Cotton Insect Newsletter Vol. 22, No. 3, June 2, 2004

Cotton Situation:  Most of the cottonseed is in the ground now.  During the past few years, growers have tended to plant a good bit of cotton behind wheat-- I wouldn't be surprised if double-crop soybeans displaced most of those cotton acres.  We are way behind on rainfall.  The weekly SC Crop and Weather Report showed that the major cotton production areas have rainfall amounts from about 6” to 10” below average for the period of Jan. 1 to May 30.  Cotton plants are still hanging in there, but when squaring begins they will need more than a few sprinkles. Newsletter Format:  This probably concerns the secretaries in County Extension offices more than anyone else, but I am changing the word processing format to MS Word today.  Previously, all newsletters have been emailed as WP files.  Since Counties have been using MS Word, the WP format has created problems for them.  I hope this does the trick.  Thanks to June Barbour for her efforts in making this transition possible.  Like many of you, my computer skills are very limited.  I can plug in a computer, I can type some words and put some numbers into a software program, but when something goes wrong with the computer-- I am not the man to call.   Cotton Insect Situation:  I just finished rating thrips damage in some cotton that was treated for the first time on May 26, and seedlings were in the 2-leaf stage of growth.   I also sprayed it for the second time.  As you might guess, the plants were already damaged rather severely when the first foliar spray went on.  Where I treated with Orthene 97, and some other insecticides, there was still a considerable amount of damage, but the plants were showing good signs of recovery.   Most of the untreated plants had a grayish-green color.  There were few true leaves and little growth was evident in terminals.  Some of the plants were stone, cold dead.  The live plants will eventually resume growing; however, I expect there will be 2-3 week delay in maturity. Fran did some thrips counts yesterday evening.   Adult thrips numbers still averaged from 4-5 per plant.   The species composition had shifted from close to 100% tobacco thrips last week to about 50% tobacco thrips and 50% western flower thrips.  There may still be a few thrips infesting newly emerged cotton seedlings, but the major movement should be over.  Warm temperatures and rapid growth will help cotton plants compensate for thrips injury.  If you see large numbers of adults and nymphs on seedlings, and little signs of recovery from the damage, it may be necessary to apply one more shot of Orthene, or another recommended material.   Grasshoppers are still nibbling away on cotton seedlings.  Last week I mentioned that the pyrethroids, Lorsban, malathion, and Sevin were some of the materials that would control grasshoppers.  Dimilin (2L @ 2 oz/acre or 25W @ 2 oz/acre) would be another good choice to control grasshoppers.  Dimilin is a growth regulator, so it would not be effective on adults, but should be applied to grasshoppers in the 2nd or 3rd nymphal stages.    Large numbers of tiny red and black bugs have been found feeding in some cotton fields below the lakes.  These are immature burrower bugs.  Usually the feeding of this species, which Jay Chapin identified as Sehirus sp., will be confined to wild host plants of the mint family, so cotton seedlings should be safe.  These insects will be found in fields where minimum tillage operations are being utilized.  If there happen to be some live plants in the field, on which they can feed, they should survive to adulthood (winged stage) and fly away.  These critters are root feeders, so if the plants they are feeding on have taken up Temik, they should be killed.  Don't get excited about these bugs.  They will not turn in to stink bugs.        Mitchell Roof  Extension Entomologist

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