Expert believes pest problems not
related to Boll Weevil Eradication
LITTLE ROCK -- Farmers and University of Arkansas entomologists thought that freezing weather in December would help reduce insect problems in the spring and summer.
"Were we ever wrong!" says Gus Lorenz, entomologist with the UA's Cooperative Extension Service.
Farmers throughout Arkansas have been plagued with higher-than-normal numbers of many kinds of insects, including armyworms, grasshoppers, stinkbugs, cotton fleahoppers, salt marsh caterpillars and plant bugs.
Lorenz said some farmers, especially in southeast Arkansas, have suggested the problems could be related to the Boll Weevil Eradication Program, which is in its third season, and its widespread use of malathion insecticide. The program seeks to control the annual boll weevil problem with a wide scale, concerted approach using insecticide sprays and cultural practices.
"In our opinion, there is no correlation with these insect problems and the program," Lorenz said. "The main reason we believe that is because these problems are appearing statewide, not just in eradication areas."
Lorenz recounted the chronology of the insect problem this year.
The spring started out with one of the worst armyworm outbreaks farmers and entomologists had ever seen. The culprit was the "true" armyworm, not to be confused with the late season pest, the fall armyworm.
The true armyworm is commonly seen in the spring in wheat growing areas. It's not uncommon for farmers to have to treat wheat for this pest. This seems to occur regularly, mainly in a small part of the state where wheat acreage is greatest. Lonoke, Arkansas and Prairie counties are where the pest seems to appear most often.
"However, this year the true armyworm was found in all wheat growing areas of the state from southwest Arkansas to northeast Arkansas, through the Arkansas River Valley and in southeast Arkansas. We observed infestation levels as high as 60-70 per square foot. That's more than 3 million larvae per acre."
As a result, most wheat had to be treated, many fields more than once. That was an additional cost that reduced farmers' profit potential.
"If this wasn't bad enough, the armyworms spread to pastures," Lorenz said. "We soon realized that infestations would be serious enough for growers to treat pastures to save their hay and seed crops. This situation is rare."
The salt marsh caterpillar then hit much of the Delta region in eastern Arkansas. This is a common Arkansas pest that rarely reaches damaging levels and always arrives late in the season.
This year, it appeared early in the spring and began to feed on cotton and soybeans. It was difficult and expensive to control, according to Lorenz.
Grasshopper populations soon showed up throughout the state, feeding on soybeans and cotton. "Soybean feeding is not rare, but cotton feeding by grasshoppers is not something we see often," Lorenz said. Grasshoppers were a serious problem in northcentral Arkansas where they defoliated shrubs and trees. This outbreak was outside the boll weevil eradication zone, Lorenz noted.
He said grasshopper outbreaks are favored by successive growing seasons with drought conditions, such as Arkansas has experienced during the last three summers.
"Mosquitoes and ticks appear to be as bad as ever," said Lorenz. "Would we expect mosquitoes to be less of a problem after a cold winter? Not really, especially when you consider the fact that in Canada mosquitoes are much more severe than here in any given spring.
"The thing to remember about many of these pests is that they have been around a long time, even when we've had colder winters than last year. To think that one decently cold winter will wipe all these pests is just not realistic."
Why late-season pests such as stinkbugs, salt marsh caterpillars and others have shown up early is anybody's guess, the entomologist said.
He said tropical and subtropical pests blow in on weather patterns out of the Gulf of Mexico. "Experience tells us these pests always hit south Arkansas first and work their way north, often running out of time in the fall when cold weather appears.
"When you look at weather patterns in late-March and April you will see we had fairly good southerly flow of air, which may have caused these pests to get here earlier than normal."
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For More Information Contact:
Gene Martin
gene.martin@arfb.com
Box 31, Little Rock 72203
(501) 228-1330