GAINESVILLE -- The Southeast is suffering through the worst infestation ofarmyworms in recent memory, with the pests chewing their way throughthousands of acres of crops, pasture and turf.
The insects' population explosion was brought on by a mild winter followedby this summer's drought, said Richard Sprenkel, pest management specialistwith the University of Florida's Institute of Food and Agricultural Sciences.
"They showed up very early but weren't much of a problem in April, May andJune because the drought stunted vegetation," he said. "The rain that beganin July activated fertilizer that had been lying dormant. Greeneryexploded, and the worms went to town.
"Early in the summer, we were getting only four to five armyworms in ourtraps each night," Sprenkel said. "Recently, we've gotten as many as 50 pernight."
The outbreak is serious throughout the Southeast, experts at universitiesin Alabama, Georgia, Louisiana and Mississippi said. "It's the worst I'veseen it in the 20 years I've been here," said Lamar Kimbrough, a cattlefeed expert at Mississippi State University in Starkville. "We're concernedthat the next wave will wipe out our winter ryegrass."
Armyworms balloon from the width of two hairs to as fat as a pencil and upto 2 inches long during their three- to four-week life span.
"When they're full-size, they move awfully quick, sometimes destroying afarm field in 48 hours," said David Holmes, Marion County extension servicedirector, in Ocala. "One farmer came in who said it was like his wholepasture was just moving."
Armyworms are eating corn, cotton, peanuts and grasses used for pasture andhay.
"We've had some pastures so decimated that we've had to move cattle just toget them something to eat," said Harrell Phillips, a veterinarian andfarmer from Morriston.
The pests also are a serious threat to lawns, golf courses and athleticfields, stripping almost all the grass leaves, said UF turfgrass specialistGrady Miller. "They wiped out new plantings of grass at two Gainesvilleplaying fields, and I'm getting calls from as far away as Louisiana.
"You can't just assume one spraying of insecticides will solve theproblem," Miller said. "They have multiple generations, and the secondgeneration can be worse than the first. It can catch you by surprise."
The critters replace their skins, or molt, six times in their life span."They do 90 percent of their damage in their last two moltings and go onoverdrive the last 48 hours," Sprenkel said.
The best weapon UF experts have found against armyworms is the newpesticide spinosad, which is licensed only for use on cotton. "It doesn'tkill most beneficial insects," Sprenkel said. "When you use it, you don'tdestroy the tiny wasps, spiders and various beetles that are armyworms'natural enemies.
"Twice as many armyworms died in cotton fields treated with the newpesticide as in fields treated with other pesticides because the pests'natural enemies helped out," Sprenkel said. "We hope the new product willbe licensed for use on other crops in the future."
Farmers and ranchers should continue to check their hay fields and pasturesfor worms through September and October, said UF cattle feed expert CarrolChambliss. "There already is a shortage of hay, and we need to applypesticides whenever armyworms are spotted so we can harvest as much of thislast cutting as possible."
The armyworms should taper off in the fall as the weather changes andthere's less food for them because vegetation declines, he said.
"What we really need is a cold winter to kill back this year's armyworms sowe don't have the same problem next year," Chambliss said. "We hope this isjust a bad year for armyworms and other pests, not part of a trend."
The above story is based on materials provided by University Of Florida's Institute Of Food And Agricultural Sciences. Note: Materials may be edited for content and length.
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