2016 Bollworms in Cotton

Below is an email from Zach Webb,  Technical Agronomist for Monsanto Company.


Webb, Zach. “2016 Bollworms in Cotton.” Message to Monsanto customers. 19 Aug. 2016. Email.

Several of you are experiencing numerous calls from growers, retailers, consultants, etc. regarding worms in their cotton. About 2 weeks ago we began experiencing a moth flight of biblical proportions. I don’t know that we have seen numbers like this in many many years.  This has led to some breakthroughs initially in Widestrike cotton.  Growers began spraying their Widestrike cotton as a widespread blanket spray. Since then, we have begun to see breakthroughs on BGII cotton as well.

Here are a few reasons why we are seeing this now:

  • Widestrike has 1 gene for Bollworm, BGII has 2 genes for Bollworm.
  • We are seeing Bollworm numbers like we haven’t seen in many years.  There are reports of scouts finding 10-15 eggs per plant and many in the blooms.
  • Cotton is running about 1-2 weeks late this year which makes it more susceptible to worms coming out of drying corn.
  • There have been other years where we saw some breakthroughs on BGII cotton.
  • BGII has never been positioned as a 100% guarantee against Bollworms.
  • Threshold in BGII cotton is 3% 2nd instar worms.
  • If you are at threshold you need to spray.
  • Avoid using Pyrethroids.  Use Diamide products.
  • Besiege, Prevathon, Coragen, Steward, Intrepid are a few good choices but there are others as well.
  • ***At the end of the day, BGII is still the premier product offered today.  (Remember, Widestrike cotton has already been sprayed 1 or 2 times) *** Academics have stated that there is no proof of resistance at this time.
  • BGIII is just around the corner and due for small limited launch in 2017 with full launch scheduled for 2018.