NEW ORLEANS — Warm winter weather led to stink bugs showing up earlier than usual this year — bad news for soybean farmers because redbanded stink bugs can destroy entire fields if left unchecked.
The threat comes as high prices and drier weather prompted Louisiana and Mississippi farmers to boost soybean acreage from last year.
Insecticides are the main restraint against the stinkbugs. LSU AgCenter entomologist Jeff Davis said farmers probably will have to spray more than usual this year. He said the AgCenter usually recommends three to five applications for soybeans, and Louisiana farmers likely will need five this year.
Mississippi usually plants more soybeans than Louisiana, and this year is no exception. Louisiana farmers have put in about 1.14 million acres compared to 2.13 million in Mississippi.
Redbanded stinkbugs destroy the crop by squirting digestive enzymes into beans through needle-like mouth parts, then slurping up the goop.
“They slurp it up kind of like a Slurpee. Like a big smoothie,” Davis said.
It’s a potentially costly problem. Last year’s prices had a record average of $11.90 a bushel, and June prices in Mississippi averaged $14.20, up 90 cents from June of 2011, said Serial Kenerson, acting director of the U.S. Department of Agriculture’s National Agricultural Statistics Service office in Mississippi.
Soybean prices nationally hit a record $16.79 per bushel Monday after a USDA report said widespread drought in the nation’s midsection has left 27 percent of soybeans in poor or very poor condition in the 18 states where most are grown, and only 40 percent was in good or excellent condition.
At $16 a bushel and 35 bushels an acre, a 100-acre field could be worth $56,000.
Mississippi is No. 12 and Louisiana 18th in soybean acreage this year with 2.13 million and 1.14 million acres respectively; No. 11 Arkansas planted almost as many acres in soybeans as Louisiana and Mississippi together.
Redbanded stink bugs apparently moved into the United States from Central and South America, and are a bigger threat in the Deep South than in more northern climates, where cold winters keep them in check, Davis said. “They’ve been found as far north as southern Missouri and Tennessee,” he said.
Farmers who have planted strains resistant to the bugs would need less pesticide, he said. Of six varieties tested over three years, one called Pioneer 95 Y20 has consistently been most resistant, he said. He didn’t know how many acres are planted in that variety, and said the most stinkbug-resistant plant may not be the best for a given area’s soil type and growing conditions.
Fire ants also can keep stink bug numbers down. “They’re a pest for us ... but they do provide a service in those fields,” he said. “I don’t think any farmer encourages fire ants. They’re ubiquitous in the fields now; they’re ubiquitous around Louisiana every year.”
Davis said farmers began calling about stink bugs in early May, almost two months earlier than usual.
“They don’t even have pods yet, and stink bugs were showing up,” Davis said.
Another indication of the early start is the speed with which they’ve reproduced in white clover, where they’re common before soybeans begin producing seeds. “We’ve documented four generations at a time in white clover this year. We’ve rarely seen more than one or two,” he said.
“We were warmer earlier, they were more active earlier, feeding earlier, multiplying earlier, he said. “There’s a good potential for them to have many generations in soybeans.”