Cotton Pest Update

Howdy,

  I know many of you are in the middle of harvesting sorghum, and that means we made it though without sugarcane aphid populations skyrocketing. That is fantastic, considering the winter we had. It never really got cold enough to kill anything. The corn is also finishing out, and a great deal of it looks pretty good, despite all the southern rust, northern leaf blight and other diseases we saw. The cotton is very near if not at cutout in most places. Most fields in Jackson and Matagorda counties are past cutout now, and the flowers are at the very top of the plant, if it's still flowering at all.

  The pests I have been seeing in cotton mostly are just bollworms. The stinkbug pressure has been pretty light, but we'll still need to keep an eye out for them for a little longer. Bollworms have started flying again, and I have seen new moths and some new eggs laid. We may have one more flush of these insects before the cotton in out of harm's way.

  The threshold for bollworms is 5,000 worms/ acre with more than 5% damaged bolls and worms larger than 1/4 inch. If you are seeing higher than about 25% of the plants with larger larvae on them, please give me a call and let me know. I have heard scattered reports of pyrethroids not working as well as expected, it may be good to keep that in mind if your fields reach treatable levels. This website has a decent chart on what insecticides work on bollworm if you do have to spray them.   

H. zea moth
Photo: Kate Harrell

H. zea eggs
Photo: Kate Harrell

Armyworm eggs
Photo: Kate Harrell

Bollworm Damage
Photo: Kate Harrell

H. zea Larvae
Photo: Kate Harrell

   We need to continue to keep an eye on stinkbugs, their populations will probably rise as grains are being harvested. There are also leaf footed bugs moving into cotton, but we can treat them the same way as stinkbugs, but err to the lower end of the threshold for them. They are aggressive feeders and tend to move in groups.

Stinkbug Eggs
Photo: Kate Harrell

Minute Pirate Bug Nymph
Photo: Kate Harrell 

Lacewing Larvae
Photo: Kate Harrell

  The beneficial populations are pretty healthy in most fields right now. I am hoping that will help with the new egg lay the bollworms have recently started. I've been bitten by two minute pirate bugs and lacewing larvae. If they're gutsy enough to bite an entomologist, they should make short work of a caterpillar. Have a safe weekend, everyone.

Kate