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Cotton production practices in Texas are as diverse as its growing regions. Even insect control strategies may differ depending on species, yield potential and cultural practices common to the region. One-size-fits-all control measures don't apply, but one thing is certain: from the Southern Rolling Plains to the Coastal Bend, worms are prevalent. And management strategies, whether for conventionally-grown or Bt cotton, must be carefully assessed each growing season. For conventional cotton, the objective is control. Careful selection of insecticides coupled with integrated pest management offer producers a cost-effective approach to stopping worms and other insects. And where insect resistance is a problem, new chemistries are needed to provide additional help. For Bt cotton, control of worm escapes and non-lepidopteran insects often require supplemental chemical application. A Powerful New Chemistry Denim® insecticide is a powerful new tool that is ideal for both conventional and Bt cotton. Used as an overspray in Bt cotton, Denim fills the need for supplemental worm control. In conventional cotton, Denim serves as a primary tool against the complete range of lepidopteran pests. Its new chemistry has added value for growers who have experienced insect resistance to older chemistries, such as the pyrethroids. With three modes of action - contact, residual and ovicidal - Denim attacks target pests on three levels and can control species that have become resistant to the classic chemistries. To understand why Denim is so effective against these pests, it helps to know how it works. The active ingredient in Denim, emamectin benzoate, causes loss of cell function and affects nerve impulses. As a result, larvae stop feeding shortly after exposure. Although it may take three to four days for death to occur, plant damage after application is minimal since feeding stops after larvae ingest the chemical. Entomologists, including Dr. Chris Sansone with the Texas A&M Research & Extension Center, have found that Denim is an effective replacement to some chemistries and, in many cases, works well in chemical rotation with older materials. "I've looked at Denim since it was a research compound," said Sansone. "I've had large field plots where we've evaluated it on producers' fields in both the Southern Rolling Plains and the Blacklands. It will have a role to play in our cotton pest management programs for a number of reasons. "Most importantly, it's effective on difficult to control worms the beet armyworm and the tobacco budworm. Many growers still use the pyrethroids on bollworm, but the pyrethroids don't work as well on beet armyworm and resistant tobacco budworm. That's where new chemistries like Denim fit in well and can complement or supplement the use of older chemistries. It's an effective material in chemical rotation." A New Pest Control Option in Cotton Because of its excellent activity against damaging worm species, Denim is a welcome addition to pest control options in cotton. Pests Denim is active against include: • Beet armyworm Linda Long, a cotton consultant from Pearsall, Tex., has seen how effective Denim can be against pests. "We had extremely heavy worm pressure this year, so we went out with our first shot of Denim, and it was 100 percent better than what we had used before," she said. "It did a better job than anything else. When we have spider mite problems late in the season and we're trying to keep that population down, it fits right into our control program perfectly. "When you're trying to take care of mites and worms, you know that Denim might have some effect on the mites," she continued. "That makes you feel a little bit better for your grower." Denim Offers Tank Mix Flexibility Denim is not only easy on beneficials; it's also easy for producers who may want to use it in a tank mix with other materials. Denim is compatible with most insecticides, fungicides and foliar nutrients labeled on cotton. It also has no known cross-resistance to any other material and is effective at very low use rates. Jimmy Barger, a cotton consultant in the El Campo, Tex., region, said Denim works well either by itself or in a tank mix. "We have to deal with worms because we're about 75 percent conventional cotton and 25 percent Bt cotton," he said. "This past year was the first year I had looked at Denim. We looked at it a couple of different ways. Where we used it alone, we put out 10 to 12 ounces per acre. Where we tank-mixed with a pyrethroid, we used 6 ounces. It performed well on worms both alone and in tank mix. Especially for broad-spectrum control, the tank mix of Denim and a pyrethroid worked very well for us." Jared Strnadel with Helena Chemical in Richmond, Tex., reported similar results. "We still have a fair amount of conventional cotton in my area so we're very concerned with worm control. I use Karate® as my insecticide mainstay. We tank-mix various materials with it depending on pests present. We used some Denim with Karate last year, and I was very pleased with the broad spectrum of control." Strnadel concludes that the future of Denim in Texas cotton looks promising. "Denim will be a very good fit under our pest management systems in this area," he said. "On its own, it's easy on beneficial insects. It's effective on secondary pests like the armyworm complex, and it's a good tank-mix partner. It will be part of my recommendations this season. In a nutshell, it provides broad-spectrum worm control at a reasonable price." University and Consultant Contacts: Chris Sansone, PhD Linda Long Jimmy Barger Jared Strnadel # # # |