The person who finds a way to predict worm pressure could get a statue to replace the boll weevil monument in Enterprise, Alabama.
Until that person comes forward, growers across the Cotton Belt are well-advised to scout fields; the only way to stay ahead of an infestation is to find them before they find your cotton.
“Be aware of what’s going on around you,” says Dr. Phillip Roberts, University of Georgia Entomologist. “Stay in tune and stay in touch.”
With Bt-traited cotton planted almost exclusively in most growing regions, growers tend to count on those traits to manage worm infestations. For the most part, they still can. Heavy worm pressure in 2016, however, showed cotton growers the wisdom of paying attention to lepidopteran pests.
2016, however, showed cotton growers the wisdom of paying attention to lepidopteran pests.
For the Southeast, cotton bollworm is most likely to exert heavy pressure. Traditionally, Roberts says, those moth flights can be expected in the Deep South starting around July 10. With warm weather early in 2017, those flights could come sooner.
Two management practices are essential to worm management:
Choose a cotton variety that includes a two- or three-gene Bt trait. For instance, TwinLink® is a two-gene Bt trait and TwinLink Plus is a three-gene Bt trait. Additional proteins in the traits increase the level of control and extend the durability of the trait by improving resistance management.
Scout your cotton to ensure worm populations are staying below the economic threshold.
Worm control should be a part of every insect treatment decision, Roberts says. “Make good decisions when treating for other insects,” he says. For instance, when deciding which material to use for a stinkbug treatment, use a tankmix that also will treat bollworm.
Growers can call on their local Bayer Technical Service Representative, agronomist or sales representative to consult on worm control.
TwinLink and TwinLink Plus Score High in Trait Efficacy
This chart shows comparative efficacy of worm control traits as rated by the Mid-South Entomology Working Group in 2016.
Source: Mid-South Entomology Working Group, 2016