Reports of increasing plant bug pressure in cotton is not unexpected as we move into July. I’ve fielded a lot of questions about what to treat with, and it is hard to get very inventive when there are only a few ‘got to’ insecticides. Acephate/Orthene and Transform are the backbone of our plant bug management program in blooming cotton. Getting Bidrin into the mix is another option. I encourage everyone to try to work in Diamond and Transform (or both) into their insecticide program. Overreliance on OP insecticides such as Acephate and Bidrin is a recipe for resistance, and mixing in other modes of action will protect all chemistries. Transform also has the advantage of keeping aphids at bay and is less likely to flare secondary pest.
There are combination applications that should be considered. Diamond is often applied in combination with Orthene or Bidrin, at somewhat reduced rates, because Diamond does not control adults. Transform at 1 oz per acre tank mixed with 0.5 lb/acre of Acephate or 3-4 oz/acre of Bidrin are excellent combinations that maintain plant bug control while improving control of stink bugs. Orthene plus a pyrethroid is always an option to consider, but I would never recommend less than 0.67 lb/acre of Acephate with this mix.
It’s time to get the drop cloths out. Treatment is recommended when an average of 3 or more tarnished plant bugs are found per drop cloth. It appears this is a year where clouded plant bugs will be a bigger part of the mix (see images below). Although relatively easy to control, they do more boll feeding than the tarnished plant bug. A rule of thumb once bolls are present is to count clouded plant bugs as equivalent to 1.5 tarnished plants bugs … and count stink bugs as equivalent to 3 tarnished plant bugs … when making treatment decisions.
I will address insecticide options when bollworms move into the picture later this month, but with the decreasing efficacy of pyrethroid insecticides, controlling both bollworms, plant bugs, and stink bugs will be a little harder on the pocket book.
Reminder – Visit the UT Pest Guides at http://guide.utcrops.com/ for app-like access to insect control recommendations in cotton and soybean.