Cotton Links


Spider Mite Problem Still Exists
In Mid-South

Spider mites are becoming an increasing problem in Mid-South Delta cotton. In Mississippi alone, cotton acres treated for mites went from fewer than 100,000 acres in 2003 to more than 400,000 in 2007, according to Angus Catchot, Mississippi Extension entomologist.

Some experts speculate that the decreased use of Temik has something to do with it. Also, less tillage leaves more winter hosts for mites, and the last few years of dry conditions haven’t helped either.

“We’ve always had spider mites at some level,” explains Catchot. “But that was usually later in the season. Now, we’re seeing them early, almost as soon as the cotton comes out of the ground in some areas of the state.”

At that point, a lot of producers would prefer for economic reasons to band an insecticide over the plant row, but that can be a mistake, says Jason Roberts, an independent crop consultant in Dyersburg, Tenn.

“First of all, if you have any vegetation between the rows, the mites unexposed to the miticide will move onto the cotton,” says Roberts. “Plus, early season is no time to be messing around. I’ve seen mite numbers so extreme that they can eliminate a stand of young cotton or at least stunt it so bad that it’ll never catch up.”

Where Are The Mites?

At the same time, “mites live on the underside of the leaves,” says Roberts. “You really need to get the miticide over the entire plant, and that’s hard to do without broadcasting it.”

Coverage is critical, he says.

“You need to use 15 to 20 gallons of water per acre, plus hollow-cone or flat-fan spray tips. Last year was especially bad. We had brutal mite populations as early as one true leaf, so we were spraying as early as mid-May.”

Most of his Tennessee producers applied Oberon or Zephyr. His Missouri producers were able to use FujiMite, which is registered for states west of the Mississippi River. In 2008, Roberts expects several of his customers will apply Portal, which has the same active ingredient as FujiMite and is now registered for use in states east of the Mississippi, as well as Louisi-ana, Arkansas, Missouri, and Texas.

“I’ve tried all of the miticides and Portal has worked as well as any of them, plus it’s priced lower, which makes it attractive,” says Roberts.

Catchot agrees, as does Gus Lorenz, Extension entomologist with the University of Arkansas.

“We’ve had Portal in our field trials for several years, and it’s done an excellent job. I expect it to be popular with Mississippi and Tennessee growers,” says Catchot.

“Portal is very effective against the two-spotted spider mite,” says Lorenz. “I rate it as one of the most effective miticides we have. Certainly, it would be an option for that early-season treatment and for late-season mites. And it’s a different chemistry, which takes care of resistance concerns.”

Expect The Unexpected

“One thing to remember is that once the cotton is out there, don’t compound the problem by using a broad-spectrum insecticide if it is unneeded, especially early in the season,” says Catchot.

He says that Bidrin and dimethoate can be used for thrips, rather than Orthene or a pyrethroid. Later in the season, once plant bugs need controlling, producers don’t have a lot of alternatives, according to Catchot.

“As long as Orthene remains a good option for plant bug control and pyrethroids for bollworms, I do not see us not utilizing these products for fear of flaring spider mites,” he says. “However, that does mean that we need to watch those fields closely for spider mites.”

Even then, insecticide applications don’t always flare mites, says Scott Stewart, IPM specialist with the University of Tennessee.

“If they did, we might recommend adding a miticide to a late-season broad-spectrum insecticide. But it’s hit or miss,” he says.

Consider Other Options

If a late-season flare-up is extensive, a true miticide might be required. If not, a less-expensive, broad-spectrum insecticide like Brigade can be applied, says Roberts. “At that stage, cotton is hardier and can stand more mites. But you still need a true miticide.”

Nichino provided information for this article.

Spider Mite Check List

• Spray early for mite outbreak.
• Check on underside of leaves.
• Eliminate extra vegetation.
• Watch for late-season outbreaks.


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