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Cotton growers brace for new insecticides

In one respect, cotton producers have never had it so good. Thanks to boll-weevil eradication and genetically altered cotton, two of the biggest bullies of cotton — boll weevils and caterpillars — have been effectively cut down to size. Even so, a few pint-sized predators remain.

“We're moving from an era in which there were a couple of dominant pests into one in which we have five or six less dominant pests,” says Ron Smith, an Alabama Cooperative Extension System entomologist. “None of these are nearly as dominant as those we've encountered in the past, but all of them can cause yield reductions in cotton.”

In the past, producers relied on broad-spectrum insecticides such as pyrethroids to combat these pests. These chemicals, in addition to eliminating the targeted pest, offered one other advantage.

“In the process of cleaning the insects targeted by the chemicals, we also cleaned up a lot of other pests at the same time,” Smith says. “That's why we referred to these chemicals as broad spectrum insecticides.”

However, under stringent new guidelines outlined in the Food Quality Protection Act of 1996, broad-spectrum pesticides such as pyrethroids and phosphates will become increasingly unavailable to producers. Instead, producers will have to rely on newer classes of insecticides that are designed to be both “target specific” (designed to eliminate only one insect) and safer for the environment.

While many of these newer insecticides are highly effective against pests, they will require producers to think and act in an entirely different way.

“In the past, producers went out with more of a preventative approach, applying a broad-spectrum chemical at predetermined intervals within the growing season to knock out a wide range of pests,” Smith says. “But in the future, we'll be taking a more reactive approach, targeting specific chemicals to specific pests only when they're detected in the field.”

The wide array of pesticides available under the new approach will afford producers far more adaptability. It also will reduce the risk of insecticide resistance — a recurring concern under the old approach. On the other hand, the sheer number and variety of chemicals also means growers will have to become more knowledgeable about pesticides than ever before.

“We're moving into a new era — a more expensive era — in which growers no longer will have the luxury of making preventative applications,” Smith says. “They're going to have to know what the problem is in the field and target their spraying just to that insect.”

This will involve monitoring each field on a regular basis in order to determine which pest is at an economically damaging level. Once that determination is made, growers, working from a list of up to 10 different chemistries, must decide which one is best suited to eliminating this particular pest while leaving the other pests alone.

Needless to say, the demand for highly trained cotton scouts will be more important than ever.

“In the old days, it was easy to focus on one dominant pest in the field, knowing that when you reacted to one pest using broad-spectrum chemicals, you would be taking care of others as well,” Smith recalls.

“However, this new approach will require a trained professional who can go into a field and look for the pest that is most likely to pose a threat during that particular week in the growing season,” he adds.

“That's where experience will count. Inexperienced scouts are simply not going to be what a grower needs. It's going to require an experienced person who can guide an inexperienced scout through the field.”

Unlike many broad-spectrum insecticides, which tended to work immediately on contact with the pest, many of these newer chemicals are slower-acting stomach poisons — far less dangerous to birds and aquatic life but far more costly to producers.

“We will have to do a better job of applying these chemicals and making sure they're ingested,” Smith says.

The slower-acting nature of these new chemicals also will affect the way fields are monitored after spraying.

“With this new approach, some of these pests are likely to linger for a few days after these applications,” Smith says. “So, a good rule of thumb is to wait a few days before returning to the fields to evaluate.”

Producers also aren't going to have to spray their cotton as often, Smith says.

“In the past, growers typically made applications at certain intervals,” he says. “In the future, he may go two, four even six weeks without applying any chemicals.”

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