Those Florida-grown strawberries you love so much in your smoothie or cereal have been under attack in recent years by a pesky invasive insect, but researchers have been workshopping solutions.
Chilli thrips are really small insects, barely visible to the naked eye, from Southeast Asia that leave dead tissue behind wherever they feed.
"This is a species that can complete a whole life cycle within five to 10 days,” said Sriyanka Lahiri, an entomologist and professor at the University of Florida Institute of Food and Agricultural Sciences.
“So that's a tremendous population to keep up with."
Production losses
The pests not only like to feast on Florida’s strawberries, but blueberries, citrus and ornamental flowers, too.
They were first documented in Florida in the 1990s, but have been threatening the state’s $400 million strawberry industry since about 2015.
"We've seen what happens to a plant when it's not rescued on time, you are looking at losses of 60 to 70% of that production value," Lahiri said.
Matt Parke is a fourth-generation strawberry grower and current vice president of Parkesdale Farms in Dover.
He said four or five years ago, his crop had a really bad outbreak, losing about a third of production, while other growers he knows have lost up to half.
“Some years … we have a very mild season of them, and then the next year it's just absolutely catastrophic," Parke said. "And you're just like, ‘What happened?’”
Tools in the toolbox
Recently, scientists at UF/IFAS bred two strawberry varieties that they say are more resilient to chilli thrips.
One of Lahiri’s PhD students, Lovely Adhikary, observed that the strawberry breeds called Florida Brilliance and Sweet Sensation had less damage from chilli thrips and higher yields than five other varieties over a few growing seasons.
"This is a five- to-six-month long crop, and so they need all the tools that they can. And our current study is an important part of that," Lahiri said.
The research was funded in part by the USDA National Institute of Food and Agriculture Hatch program.
For strawberry growers like Parke, the most effective way to combat this bug so far has been rotation of insecticides because chilli thrips quickly become resistant to the effects.
“You hit them hard and heavy, then you back off of them for a little bit,” he said.
“You're never going to get rid of them in your field, but what you're trying to do is keep them suppressed. And if you get over-reactive and hammer them … with different chemistries … all that's doing is making a super bug that is resistant to the chemistries you're trying to give to it.”
ALSO READ: Why Florida's strawberry season was so 'tough' this year
Parke said he hadn’t seen the recent study out of UF on the more resilient strawberry varieties, but that from his experience chilli thrips will jump on “anything and everything.”
“Saying that one variety for is more resilient against chili thrips … I can tell you this: that in my Brilliance field to my Sensation field to my Encores field to my Embers field, there's no difference to me,” he said.
Parke said he’s is looking forward to learn more about the study at a presentation this summer.
Organic fields
As for solutions to infestations on organic strawberries, UF/IFAS PhD student, Allan Busuulwa recently published a study on using banker crops, like ornamental peppers, to attract predators for the chilli thrips.
There’s also the option to use botanical oils that would discourage the pests from sticking around.
Parke said, the thing that’s worked best on his organic field is to manually remove them, one by one.
“That's the only thing you can do. I mean, the stuff that you're putting out on organics, really, it might work at a 10% rate, maybe, and it's very expensive, and there's not a real cure for it,” Parke said.
While chilli thrips have been a problem for Florida growers the past decade, recent hurricanes Helene and Milton also hit the industry hard this growing season.
“I'd say the hurricane cost me a lot more money than chilli thrips did this year. I would say my chilli thrips population was manageable this year,” Parke said.
Warm temperatures
Lahiri said a warming climate may be helping chilli thrips spread throughout the U.S.
"If the winter's getting smaller and warmer, then even these biotypes that couldn't have survived in those environments before, are going to thrive," she said.
“And as it warms up, the environmental deterrents will play a certain part. But as those detriments start going away, this insect is just going to do what it does best, reproduce and feed on many different plants and just invade more areas and more crops.”
The insects have also recently been found in Georgia, Texas, New York and Pennsylvania.
“They're spreading fast. This insect is expanding its geographic range within the continental United States,” Lahiri said.
