Stink Bugs

Researchers at LSU predict higher numbers of redbanded stinkbugs following a series of mild winters in Louisiana.

Fred Collins is used to warding off pests from his farm fields. But over the years a particular pest has him more on guard because of the potential damage it can cause.

Recently, he found a group of redbanded stink bugs nestled under some clover and weeds at the edge of his soybean field in Avoyelles Parish — an odd find for mid-February. In past growing seasons, he’s sprayed his fields only to come back a few days later to find more.

“We thought we killed them all, and we had to turn around and spray them again,” Collins said. "I let my guard down and they jumped back up on me pretty quick.”

Farmers like him aren’t likely to get much relief this year from the stinky insects, which can wreak havoc on farms as they munch their way from field to field gorging on soybeans and other crops.

Researchers at the LSU AgCenter recently raised alarms about a potentially worse year for redbanded stinkbug infestations because past mild winters haven't put a significant dent in their populations in Louisiana.

Though parts of southern Louisiana have dipped below freezing a few times in the past two years, redbanded stink bugs have withstood the cold because temperatures didn't drop below 20 degrees long enough to kill the neotropical bugs that are native to South America.

“They’re not freezing to death and they have plenty of food,” said Jeff David, an entomologist at the LSU AgCenter. “There’s a good chance these stink bug numbers are going to be pretty high this year.”

He and other researchers are warning farmers to be extra vigilant about safeguarding their fields and taking measures like burning cover crops and checking their bean plants more often.

Stink bugs get their name from the pungent odor they emit to ward off threats. Though they don’t bite or sting, some people have reported reactions like runny noses and other symptoms similar to an allergic reaction.

In Louisiana, they often scurry under protective plant covering in farm fields or ditches in the colder months. Recent winters have provided them with an abundance of plants like clover and other legumes to tide them over until their favorite — soybeans — are growing.

Davis and other researchers predict higher numbers of infestations could also add financial stress on farmers, including higher bills for pesticides and damaged beans.

The timing isn't great, either. 

Louisiana soybean farmers are coming off a tough growing season worsened by heavy rains that flooded fields. Market turmoil in the midst of the country’s ongoing trade disputes with China -- the largest importer of American soy products -- has also compounded their struggles to fetch prices above $9 a bushel, which is seen as a break-even price.

Soybeans are a major agricultural product in Louisiana with a farm value of $800 million, second only to sugar cane.

Harold Lambert, an independent entomologist who consults farmers in Pointe Coupee and Avoyelles parishes, stressed the importance of timely control measures to help growers make a profit in an already tight market.

Stink bugs damage soybeans by piercing the skin of fruit and beans and sucking fluid out of immature beans. Grain elevators reduce the price they'll pay for blemished beans or, in worse cases, turn some away entirely.

Though farmers in Louisiana have been fending off the pesky critters for several years, Lambert said once they infest a field, they can be difficult to kill. Often he sees a mix of adult and younger ones, which is sometimes more difficult to eradicate.

"Their ability to spread is impressive," he said.

Missing part of a field with insecticide can also lead to greater chances of fields suffering serious infestation, said David Moseley, Louisiana Extension Soybean Specialist.

“If you treat your field and miss a spot and you go back, you’ll see the difference fast,” he said. “They’ll take out the whole field.”

Davis recalls 2017 being an especially bad year for farmers, following a similar streak of warm winters in Louisiana leading up to planting season.

Though Louisiana farmers saw more infestations that year, states in the Mississippi Delta, including Mississippi, Arkansas, and Tennessee fared far worse. Some growers there even stopped harvesting because the infestations were so bad.

"A good way to mitigate that is to be aware. Sweep early and sweep often and be aware that there's a potential for these insects to be around," Davis said.


Email Youssef Rddad at yrddad@theadvocate.com.