Bollworms, other pests, showing up very early in Arkansas crops

Bollworms, other pests, showing up very early in Arkansas crops

Pest population boom arrives early in Arkansas crops. Bollworm trap numbers spike, scouting urged. Other extremely high pest populations, treatment options discussed.

The lack of prolonged winter weather followed by a spring that broke many high temperature records was bound to have an effect on Mid-South crops. That has certainly proven out with the early arrival of the insect complex.

In mid-April, Gus Lorenz, Arkansas Extension entomologist, began running bollworm traps. At this time of year, 20 to 30 bollworms are normally collected per trap.

“The first week of May, the trap counts were way outside the norm,” said Lorenz. “We’re averaging almost 400 moths per trap. Some of the traps had over 1,000 moths each. We just don’t get those kinds of numbers this time of year.”

Farmers weary of the pest are receiving no break as this season’s early numbers boom follows a bollworm-heavy 2011. The truly worrying thing is that, last year “we didn’t see these populations until June. Farmers certainly remember how bad bollworms were last season. These pests are at least a month ahead of schedule.”

Lorenz, interviewed by Farm Press on Monday (May 7), spoke on the need for producers to begin scouting now, the spike of all sorts of pest populations through the state, input expenses and treatment concerns. Among his comments:

More on bollworms…

“There are a lot of bollworms out there, right now. Question is: where are they going and what are they laying eggs on? There aren’t very many places for them to lay eggs. Seedling soybeans and knee-high corn and wild hosts are available. 

“With these numbers, I’m concerned that we’ll begin seeing some bad defoliation on seedling soybeans. We’ve never had to deal with this situation in whorl-stage corn so we’re not sure what the impact of these worms will be, or the extent of the damage they’ll cause.

“Certainly, though, growers and consultants need to be aware of the threat. They need to be out scouting already because the bollworms will show up somewhere. The bollworm larvae will begin hatching soon. Damage from them will likely pop up in soybeans and corn – particularly refuge corn -- at the tail end of this week and into next.”

On garden webworms and armyworms…

“A couple of years ago, there was a garden webworm outbreak. This year, garden webworm and fall armyworm numbers are pretty high already in the soybeans.

“Usually, those kinds of pests aren’t a concern in seedling soybeans at this time of year. Not this year – the insect activity for this time of year is as high as I’ve seen.

“And we’re coming off a true armyworm population that was in the wheat crop. That population ended up moving into corn and rice. We had a lot of damage from true armyworms in rice. This is one of the worst true armyworm infestations I’ve seen in my career.”

On tarnished plant bugs and budgeting for extra treatments…

“With this warm spring, my concern is not only with the bollworms. Let me tell you about tarnished plant bugs – the Number One pest in cotton. Right now, we can go out almost anywhere in our cotton-growing region, make 10 sweeps in a wild host, and find over 100 plant bugs. That’s happened for the last several weeks. We’ve seen those numbers around Marianna and Pine Bluff.

“All this means the pest pressure will require extra sprayings and it will be expensive for our growers. They need to prepare for at least one or two extra insecticide applications.”

Wild hosts, rice stinkbugs, beneficials

Are you seeing problems statewide or are there worse pockets?

“This armyworm infestation hit hard in the south of the state. But it’s been just as heavy, or maybe worse, in the northeast.

“It looks like it will be a statewide issue, that the insects will be bad everywhere.

“A lot of rice stinkbugs went through the wheat crop. We’re still seeing those on wild hosts, right now. There are enough wild hosts to sustain them. Rice stinkbugs were bad in 2011 and, while levels may not be quite as high this year, they will be a problem once rice begins to head.”

More on the mild winter/warm spring…

“The growing conditions this spring have been exceptionally good for wild hosts. That’s also good for the pests that build up on those weeds. All the numbers are extremely high for nearly every pest we’ve got.

“With the mild winter, it’s not a big surprise that the pest numbers are higher than normal. But the level of populations so early is a surprise.

“We’re already getting reports of spider mites on seedling cotton in the Bootheel of Missouri and northeast Arkansas.

“Western flower thrips are also moving through the state. Those began in Louisiana, I believe, and have now hit a lot of Arkansas cotton. That cotton had a seed treatment and the western flower thrips waited it out. They’re now banging up some of the earliest-planted cotton from southeast Arkansas up to Marianna.

“Thrips numbers are also extremely high in early-planted crops.”

On treatment options in an unprecedented situation…

“My biggest concern in soybeans is with garden webworms, fall armyworms and, yellowstriped armyworms. Those caterpillars normally show up in late June or July, and hardly ever are at damaging levels.

“I worry that a lot of pyrethroids will be applied early, probably the worst scenario for conserving beneficial insects. We need to save our beneficial complex as much as possible.

“My suggestion is to stay away from the pyrethroids this early. Try to use an alternative chemistry like Intrepid or Tracer – something that doesn’t disrupt the beneficials.

“In cotton, a lot of applications for thrips will reduce our beneficials and make mite and aphid problems worse.

“We really need to make applications of insecticide only as needed. Convenience applications or spraying an insecticide because you’re going across the field for something else can actually cause more problems than it will solve. There will be plenty of opportunities to spray for insect pests this year, I guarantee it. So, spend your money wisely, only as needed.”


On May 11, Farm Press again spoke with Lorenz who said his earlier fears were well-founded. “The worms are definitely hitting soybeans – bollworms and other lep pests. We’re picking up a whole complex of worms.”

Corn is yet to be as badly hit. “I guess they’re still small and down in the whorl.

“The worms are only about 25 percent to half-grown, right now. Some folks still aren’t picking them up. But I’m getting a lot of worried calls, particularly in the southern half of the state.”

Lorenz expects the week of May 14 “to give us a good idea of how bad these pests will be.”

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