Our earliest cotton is beginning to square, and I think a few reminders are in order.
- Be aware that the first squaring fields in an area will often suck in a lot of adult plant bugs. They frequently concentrate in these fields until more cotton begins to square.
- The recommended treatment threshold for tarnished plant bugs during the first two weeks of squaring is 8 per 100 sweeps. Remember the goal is to get through the pre-flowering window with 80% or higher square retention. Thus, if you drop below 80%, you may need to reduce your threshold to let the plants recover.
- The primary products I recommend during early squaring are Centric (1.75 – 2.0 oz/acre) or full labeled rates of imidacloprid. Some will even mix the two, usually cutting the Centric rate back. This does not add much to the overall cost considering imidacloprid in very inexpensive.
- Some other options to consider are Belay or Transform. I’ve not done a lot of testing with Belay, but my data indicates it efficacy is similar to the other options listed above (perhaps somewhere in between imidacloprid and Centric). Transform at 1.5 oz/acre would fit here, but I prefer using this product just before and during early bloom for a couple of reasons. Mostly, I’m trying to use the difference insecticide classes in a logical sequence starting with the neonics like Centric and imidacloprid, switching more to products like Transform and Diamond, and then relying more on products like Orthene and Bidrin later in the season.
- There are no insecticides that provide two weeks of effective control of tarnished plant bugs. Indeed, there are no products that provide more than 5-7 days of meaningful control should plant bugs re-infest a field. It is very possible you will have to re-apply an insecticide next week.
Try to use neonicotinoid products like Belay, Centric, Imidacloprid and Strafer (acetamiprid) almost exclusively prior to bloom. That is where they work best, and we must lay off this class of chemistry as the season progresses to reduce the chances of resistance.