Chilli thrips plague farmers worldwide, but new research from the University of Florida has found two strawberry varieties that show less harm from these pests.

The finding comes through research funded in part by the USDA National Institute of Food and Agriculture Hatch program.

That’s helpful news for growers in the $400 million-a-year Florida Strawberry industry because if chilli thrips are not managed properly, they can damage up to 60% of a farmer’s crop.

As of last season, growers harvested 14,000 acres of strawberries in Florida. Strawberry yield per acre can be increased with better pest management decisions, scientists said.

Over the past 20 years, chilli thrips, known scientifically as Scirtothrips dorsalis Hood, has spread from Asia to Florida, Texas, Georgia, Alabama, Louisiana and the northeastern United States. Among its victims: hydrangea, pepper, eggplant, mango, citrus, grapes, blueberries and strawberries.

As chilli thrips expands its geographic reach, scientists seek ways to control the pest. One way is through “host plant resistance,” a plant’s ability to withstand pests and diseases or to tolerate damage from them.

A strawberry plant damaged by chilli thrips at the UF/IFAS Gulf Coast Research and Education Center.

Photo courtesy Sriyanka Lahiri - UF/IFAS

Host plant resistance enables strawberry producers to use less chemical spray and other pest management tools.

For new research, UF/IFAS scientists studied UF/IFAS-bred strawberry varieties. The study, led by doctoral student Lovely Adhikary, shows Florida Brilliance and Sweet Sensation exhibited less damage and higher marketable yield than five other UF/IFAS-bred cultivars over three strawberry growing seasons at the Gulf Coast Research and Education Center (GCREC).

That means if growers choose to grow Florida Brilliance and Sweet Sensation, they can use less pesticide to control the thrips, Adhikary said.

Still, Sriyanka Lahiri, an assistant professor of entomology at GCREC, cautions that growers must continue to use integrated pest management to control chilli thrips, particularly because the study showed several strawberry cultivars that are still highly susceptible to the pests.

“The new finding is important to both growers and the UF/IFAS strawberry breeding program because now producers know that if they grow a certain strawberry, they may have to be more proactive regarding chilli thrips management,” said Lahiri, who serves as Adhikary’s faculty advisor. “They’ll have to utilize integrated pest management techniques because chemical control alone is not an effective tool to manage this pest.” Kenneth Parker, executive director of the Florida Strawberry Growers Association, calls the new findings “critically important,” especially as UF/IFAS strawberry breeders, including Vance Whitaker, try to find the genetic markers for host plant resistance.

“Selecting cultivars that have some level of defense against chilli thrips is a game changer,” Parker said. “Chilli thrips are very expensive to control, and even the best control measures are not adequate some years for a profitable season.”