With the success of two major pest eradication efforts, Western cotton producers continue to keep an eye on insect pressures and potential resistance issues.
Dr. Timothy Dennehy, global insecticide resistance manager for Bayer CropScience, says that what the pink bollworm eradication effort has accomplished is amazing.
“Nowhere else in the world was pinky pressure tracked as well as it was in Arizona,” says Dennehy.
Dennehy also says he would be very surprised if there are any changes in pinky pressures in the coming decade because of stacked gene technology.
However, the success with the pink bollworm eradication program highlights an ominous fact.
“The sad reality,” says Dennehy, “is that I cannot identify a major advancement in IPM (integrated pest management) that is not a result of a devastating tragedy in the field.”
This particular situation is exactly why all producers must keep looking to the horizon to identify future issues in pest management.
Looking To The Future
Dr. Pat O’Leary, senior director of agriculture research at Cotton Incor-porated, agrees with the forward vision concept when it comes to pests.
“There has been some slippage in effectiveness,” say O’Leary, regarding some crop protection products.
The adaptability of silverleaf whitefly is an example of rapid resistance to conventional technologies when populations exploded in the 1990s. The problem was abated when insect growth regulators (IGRs) were rotated into treatment programs.
However, some IGRs are now becoming less effective, according to O’Leary.
Dennehy believes, however, that because fewer broad-based insecticides were used, natural enemies of whiteflys flourish in the cotton environment. Predatory insects are having a huge positive impact on whitefly levels.
Indications are that even resistant populations of whitefly found in greenhouses and laboratories have not affected Western producers negatively.
“They just don’t do well on cotton,” says Dennehy.
But, that doesn’t mean researchers in Arizona, such as Peter Ellsworth at the University of Arizona, are not keeping an eye on possible issues with whitefly resistance.
According to Ellsworth, the Q biotype whitefly has been seen in green- houses for about eight years. It is highly resistant to chemical treatments, but in the United States it has not been found to survive well in the field.
“The fear is not as great as it was eight years ago,” says Ellsworth regarding expanding populations. But, he agrees that producers and research-ers need to be vigilant.
As an entomologist, he also says he would bet on the insect when it comes to survivability.
Lygus – A Local Problem?
According to Paul “Paco” Ollerton, a Pinal County cotton producer and chairman of the Arizona Cotton Research and Protection Council, there were a few concerns with lygus populations, but the problem possibly may be local in nature.
At this point, conventional crop protection products work well on keeping lygus in check. Carbine (flonicamid), a feeding inhibitor, is a selective technology used in lygus control that is not as destructive to the beneficial populations of insects.
One fact that Western producers and researchers are well aware of is exploding populations. While there is little concern about the current expansion of kudzu bug populations in the eastern Cotton Belt, the West is keeping a close eye on the situation and watching how the stink bug issues are being handled.
Stink bugs are easy to kill with conventional technology, but Ellsworth believes that the arsenal is lacking. He also is aware that the desert is tough on insects, and many of the West’s potential problems are thwarted environmentally.
While most Western producers are treating for insects on the average of only one and one-half times per season, farmers know from experience that they need to keep a diligent eye out for the next hit to their operations.
Brent Murphree is the Cotton Board’s Regional Communication Manager for the West. He resides in Maricopa, Ariz.