As most of you know, the label for Transform WG insecticide was revoked at the end of last year. A Section 18 is pending which would allow the use of Transform in cotton, but it is very possible that we will not have access to Transform in 2017. Even if the Section 18 is granted, there might be significant restrictions on its use. So what is the plan to manage tarnished plant bugs in cotton if Transform is not available? Really, my strategy remains similar to previous years.
I’m suggesting Centric (1.75-2.0 oz/acre) or maximum labeled rates of imidacloprid for applications made prior to bloom when mostly adults are present. Belay at 4-6 oz/acre is another option. Once nymphs become more common, and definitely after first bloom, we need to switch to other chemistries. This would normally be the window when I would suggest using Transform. Now, our options are limited. We will be relying heavily on Orthene/Acephate (0.75 lb ai/acre is generally an adequate rate) or Bidrin (6-8 oz). The first couple of weeks of bloom is a good time to get Diamond in the mix. Diamond at 4-6 oz/acre can and generally should be tank mixed with Acephate or Bidrin. In this tank mix, you can probably back off the rate of Acephate and Bidrin (but just a little bit). As we get closer to August, really the best option is to stick with Acephate or Bidrin. This is the window where I often recommend tank mixing with a pyrethroid insecticide to pick up stray stink bugs and bollworms (and it adds a little kick to plant bug control).
A good crop consultant is needed to help make these treatment decisions. It is concerning how few insecticide classes are available to effectively manage plant bugs, and this makes resistance management difficult. Because neonicotinoid resistance in cotton aphids is now pretty widespread, and because we may not be able to use Transform, you might expect more than usual problems with this pest.
Other than the above points, fundamental management practices that promote crop earliness will also help. Do not over fertilize. Data shows that 80 lb of N is an optimum for most fields. Select early maturing varieties and use plant growth regulators appropriately for these varieties, and irrigation should be adequate but not excessive.
