From: Jack S. Bacheler
Thrips and Late Cotton
This is Jack Bacheler at North Carolina State University with the Wednesday, May 18 Cotton Insect Update.
This past week's weather has been a mixed bag for cotton, with moisture levels generally acceptable, but nighttime lows on the cool side for this time of year and a 5-day forecast for more of the same. Generally, recent insect pressure across the state has been modest.
So far, we have not had the consistent hot, dry weather typically associated with large numbers of migrating thrips. On the other hand cotton is off to a slow start in most parts of the state. Remember that the thrips protection provided by seed treatments on cotton planted on May 1st will have ended by about May 20, irrespective of weather. As a general suggestion, cotton should be checked three weeks following planting for thrips damage. Alternatively, this cotton can be treated with a foliar insecticide at the first true leaf stage, all the better if this treatment coincides with an early glyphosate or glyphosinate application. In the case of 4 to 5 pounds of Temik 15G at planting, with cotton already up to a stand we should have good enough moisture for 4 or 5 weeks of thrips activity after planting. Field to field situations differ, however; therefore, spot checks for "thrippy" growth should be undertaken in at least a handful of fields several times a week. A blast of several consecutive 90-degree days could change the thrips picture in a hurry.
As a modest cost-saving measure, for cotton planted after about May 20, a Gaucho Grande or Cruiser seed treatment or Temik at the lower 3 to 3.5 pound rate in non-nematode fields should get producers through the "thrips window" in most circumstances.
When cotton reaches about the four to five true leaf stage with adequate moisture, thrips, though present, should no longer be an economic problem.
As of this May 18 update, we're still a good 3 weeks or so away from possible plant bug feeding on squares in early cotton. Reports of cutworm damage to seedlings in reduced tillage cotton have been minimal.
We'll provide the next week cotton insect update this coming Wednesday, May 25