Tuesday, July 27, 2010

Statewide Cotton Insect situation

We have reached the point in the season that it is difficult to generalize about the cotton insect situation statewide. Some fields have been sprayed while some have not. Some of those sprayed have received a pyrethroid while others have received a phosphate such as Bidrin for bugs only. Scouts are reporting that behind pyrethroid sprays they are finding escape worms in some fields and escape bugs (both plant bugs and brown stink bugs) in others. More escape worms are being reported in DP555 (sirge gene) then the Bollgard II varieties. As each day passes more field people are reporting Fall armyworms in blooms. It is suspected that the extreme heat has reduced the effectiveness of the pyrethroid chemistry. This happened in the early 1980's, with the earlier generation pyrethroids, when the temperatures approached 100° F.

My suggestion would be to target the insect that is potentially the most damaging. If the problem is escape bollworms I would continue to select a pyrethroid. Use a high labeled rate, add some crop oil to the spray mix, and add a phosphate if high levels of bugs are present. If the problem is primarily bugs, then just go with a phosphate such as Bidrin at 1 gallon to 21-24 acres. If Fall armyworms are in the mix the pyrethroids will not give acceptable suppression. Under this condition, I would go with Diamond (9 oz) Steward (11 oz), Belt (3 oz) or Tracer (2.5 oz).

Soybeans- A few green cloverworms and soybean loofers can be found in many fields at non damaging levels. The greatest insect threat statewide is likely stink bugs. The stink bug population has been primarily brown's up to this point. However, yesterday at the Gulf Coast Research Station, the southern green stink bugs were out numbering the browns. Also, at this site the recently discovered red banded stink bug was present and had done heavy damage to beans at the R-5/6 pod filling stage.