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Thrips Update In Cotton
DR. SCOTT STEWART
JACKSON, TENN.
Thus far, reports are that thrips populations have been relatively light but picking up. The forecast model (http://climate.ncsu.edu/CottonTIP) has been predicting that cotton planted after May 15th will face the highest infestations of tobacco thrips, and it appears accurate. Having said that, there are other species of thrips that infest cotton. Dr. Heather Kelly has a test located in Jackson that was planted in early May. It includes treatments that do not have an insecticide seed treatment and are getting “smashed” with thrips injury. The good news is that the cotton looks pretty good where a seed treatment was used (Aeris). This goes to show that scouting is still important and at-planting treatments are very important.
I’m adding an update to this article because I’ve had several questions about the use of Radiant or Intrepid Edge for thrips control. Radiant contains spinetoram at a concentration of 1 lb ai/gal, whereas Intrepid Edge contains spinetoram at 0.5 lb ai/gallon. Thus, if you use Intrepid Edge at 3 oz/acre you will get an equivalent rate of spinetoram as in 1.5 oz of Radiant. In my recent tests, Radiant or Intrepid Edge has been more consistent than Acephate at controlling thrips. However, both are more expensive than acephate. Intrepid Edge is being promoted more than Radiant because it is cheaper. Radiant and Intrepid Edge need a surfactant, but this is probably not necessary if co-applying with Roundup (glyphosate) or Liberty (gluphosinate).
Is it worth the money? I’d definitely consider using Radiant or Intrepid Edge where you are relying only on imidacloprid for thrips control. Specifically, I’d be less inclined to use Radiant or Intrepid Edge where Aeris (thiodicarb), Avicta (abamectin), or Acephate was also applied to the seed. In contrast, I would not expect Poncho/Votivo to help much with thrips control.
Remember – These insecticides cannot be co-applied with dicamba on dicamba tolerant cotton. ∆
DR. SCOTT STEWART: IPM Extension Specialist, University of Tennessee
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