I’m re-running this post as we start planting cotton in Tennessee. If you believe the thrips forecast models developed by NCSU, and my experience is that it works well, then thrips populations are behind schedule. Thus, if we can get some cotton planted in the next 7-14 days, there is a good chance the cotton can outrun thrips before populations peak. Of course, weather is still a significant factor in how badly thrips impact seedlings.
Thrips Infestation Predictor for Cotton – http://climate.ncsu.edu/CottonTIP
Our options for thrips control in Tennessee are mostly unchanged, but there are some key points you should remember. Imidacloprid is the only base insecticide seed treatment that, in my opinion, you should consider. In reality, it is the only base insecticide treatment being sold in our area. Adding other seed treatment components MAY reduce the need for foliar insecticide applications for thrips control, depending on what it is. This can reduce the likelihood of needing a foliar application for thrips. This can be important because NO INSECTIDICIDES are approved for tank mixing with applications of any dicamba products in cotton.
- An acephate seed treatment is labeled for use in cotton at a maximum rate of 6.4 ounces of 97% Acephate or Orthene per 100 pounds of seed (or a comparable rate of 80% Acephate). This is NOT considered a standalone treatment but can be used to supplement a base treatment of imidacloprid.
- The nematicidal components found in Aeris (thiodicarb) and Avicta Elite Plus (abamectin) will often enhance thrips control.
- The Acceleron “Standard” seed treatment that is available on Delta Pine varieties is treated with imidacloprid. The nematicidal option in the Acceleron “Elite” option is Poncho/Votivo, and it will NOT add much in terms of additional thrips control.
- PhytoGen TRiO is being offered as an option on WideStrike varieties. The base insecticide is imidacloprid. It also contains a biological nematode control component that will NOT have efficacy on thrips. However, both Acephate and Dimethoate are labeled for tank mixing with the Enlist One herbicide.
If I look at the data collected in Tennessee on performance against thrips, I would rate thiodicarb (as in Aeris) as slightly better than abamectin (as in Avicta Elite Plus). A supplemental acephate seed treatment has not added much in my tests, but it has improved protection from thrips in tests at other locations in the Mid-South.
A take home point is to know what’s on your seed to help plan and make better decisions about the need for a foliar insecticide application to control thrips in cotton. This includes seed being treated at the local retailer level.
Take home point number two is that almost all data indicates that a foliar application for thrips should be made at or before the second true leaf emerges.