New study says UV lamps can help manage pest in strawberry fields

Strawberries are worth $399 million annually in Florida, with about 11,000 acres in mainly west-central Florida. Most of the domestically produced winter crop in the U.S. comes from Florida and makes up about 10% of the national strawberry value.

Those economic figures make it critical for strawberry growers to keep pests and diseases at bay.

When producers began planting for the 2022 harvest in October, they were acutely aware of the potential scourge of the two-spotted spider mite, which eats into their fruit. Farmers find it difficult to manage the bugs and pathogens with conventional sprays.

University of Florida scientists recently found that by shining ultraviolet light on a field of strawberries in the middle of the night, they can zap spider mites, according to a news release.

In a new study led by Sriyanka Lahiri, assistant professor of entomology at the University of Florida/IFAS Gulf Coast Research and Education Center, university researchers have found UV lamps can effectively control the mites by applying light twice a week at night.

The study gives scientists and growers data about the amount of UV light necessary to significantly reduce the number of spider mite eggs in strawberry fields — without affecting fruit yield, Lahiri said in the release. Soon, scientists hope commercial farmers will be able to use this method.

“Since very few miticides (sprays) are currently effective in suppressing two spotted spider mites in strawberries, the use of UV light provides an effective physical control method that can be used in fields and in high-tunnel strawberry production systems,” Lahiri said in the release. “If left unmanaged, this pest will feed voraciously on leaves and cover the plant with webbing, causing tremendous fruit loss.”

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Scientists need more field trials to further confirm the benefits of the UV light treatment on the mites as well as other pests, such as thrips. Because spider mites and thrips are more difficult to control using these doses of UV light at night, scientists need to explore a combination of insecticides and higher doses of UV light.

“An added advantage is that UV light does not leave any residue behind and can be applied using automated robotic units already in production by commercial sources,” Lahiri said in the release.

Researcher Natalia Peres, a plant pathologist at the UF/IFAS Gulf Coast Research and Education Center, has already shown that a UV lamp can thwart strawberry pathogens in the field, and she sees more possibilities for the UV lamp technology.

“UV is another tool in the growers’ constant fight against pests and diseases,” Peres said. “It is particularly effective against diseases and pests that are present on the surface of the plants. Thus, other tools are still needed for those pathogens that are more deeply colonized into the strawberry tissue or flying insects that might not be present at the time of the application.”