Many consultants are reporting a real upswing in tarnished plant bug numbers in cotton this week. This includes our own cotton here in Jackson. Much of the cotton is at bloom, plus or minus a week, and tarnished plant bugs appear to be just about the only pest in most fields. A few people have reported seeing some brown stink bugs, but I’m not too worried about them until this cotton has a few more bolls on it. The common question has been … what should I spray? Below I’ve listed some options with a few pros and cons. Again, I’ll remind you that entomologist in the Mid South have gone to considerable effort to rankthe performance of many insecticides. You can see these rankings in the linked document here.
Centric or Imidacloprid: These are still good choices for cotton prior to bloom. I suggest switching off these products once blooming begins for resistance management reasons and because they tend to start “slipping” once immature plant bugs are present. Centric is more consistent than imidacloprid, but lean towards Centric at 2 oz/acre if facing higher numbers of plant bugs. Use the maximum labeled rate of any imidacloprid product. Neither Centric or Imidacloprid is great at controlling stink bugs, and they have no activity on bollworms.
Transform (1.5 oz/acre): This is a good time to consider using this new insecticide from Dow AgroSciences. Pros – A unique mode of action with excellent activity on tarnished plant bug. We need to start working this product into our programs. It is also good at controlling aphids at even lower rates. It will not smash beneficial insect populations. Cons – It’s going to cost about $9-11/acre. It lacks activity on bollworm and is weak on stink bugs, so be sure to consider this as the season progresses and these pests become more common. I’ve had several questions about cutting rates and mixing with Acephate, Bidrin or other products. I’ve done a little testing but don’t have enough data to go out on a limb (at least publicly). If you are going to be creative, do so on a limited number of acres before going whole hog!
Orthene or Acephate (0.67 – 0.75 lbs ai/acre): This is also a good time to consider using Orthene/Acephate. Pros – Relatively inexpensive and one of the top 2-3 products for controlling plant bugs and stink bugs (especially brown stink bugs). Cons – Acephate is not soft on beneficial insects (and neither are any of the options listed below).
Bidrin (6 – 8 oz/acre): This product can’t be used until blooming has begun. Otherwise it has a similar fit as Acephate (and pros and cons). It’s a good choice but just a little less consistent at controlling plant bugs than Acephate or Transform. Its super at killing stink bugs. This product needs to be handled with care, including communicating with crop advisors to make sure they know when fields were treated.
Vydate CL-V (12 – 16 oz/acre). Pros – A carbamate insecticide, so a little different mode of action than Bidrin of Acephate. Cons – Vydate is not my first choice, but it has fit is similar to Acephate and Bidrin. Again, use extra caution when dealing with this insecticide.
Diamond (4 – 6 oz/acre): Pros – Another unique mode of action that we should get into the game. This product is slow acting but provides some longer-term benefits for controlling immature tarnished plant bugs. This does not mean you won’t have to retreat, but it can keep immature populations from building as quickly or to very high levels. This can improve control with follow-up treatments. Although not an annual problem, especially with Bt cotton, it provides residual control of fall armyworm infestations. Cons – Diamond does not control adults, so you often need to add a tank mix partner if many adults are present. One application of Diamond against a bunch of immature plant bugs will not impress you. It’s best fit, in my opinion, is to use Diamond as part of your program as a mix partner with several of the insecticides mentioned above. It may not provide much downstream benefit where plant bug pressure remains low. I would definitely try to get Diamond into the mix where we have historically high populations of plant bugs (e.g., Delta type environments). It does not control adult stink bugs and only has modest effects on bollworm.
I would generally avoid tank mixing with any pyrethroid insecticides at this time. I don’t think they will add much … consider investing the same money by using the higher rates of the insecticides listed above. We will be doing more with pyrethroid tankmixes in 2-3 weeks when stink bugs and bollworms become a more serious considerations. Do not use pyrethroid insecticides alone for control of tarnished plant bug! You will be disappointed.
