UF researchers go high-tech to fight invasive plants

March 18, 2008

GAINESVILLE, Fla. — Jim Cuda is a matchmaker, but he doesn’t help lonely hearts find love. He finds organisms to fight invasive plants running amok in Florida.

An associate professor of entomology, Cuda is one of several scientists with UF’s Institute of Food and Agricultural Sciences who researches insects and pathogens that keep the pest plants in check on their home turf.

After conducting overseas field studies and extensive laboratory research to prove these organisms are host-specific, the natural enemies are released with government approval, to provide long-term control of the target plant species.

The practice is called classical biological weed control. Though it’s been around for decades, genetic analysis has added a new dimension.

“Without the technology to do genetic matching, you’re just guessing, basically,” Cuda says.

Here’s why — natural enemies may be highly adapted to a plant, even adapted to minor genetic variations found only in a particular area. Over time, enemies develop their own genetic variations to “match” the host plant, he said.

So a moth that devastates Brazilian peppertree in one place may have much less effect 500 miles away, because the genetic variations don’t match as well.

Genetic analysis lets researchers examine a pest plant found in Florida and work backward to pinpoint where it originated.

Then researchers travel to the plant’s native range and collect natural enemies. At the laboratory, they examine the performance of the natural enemies on plants with the genetic variations found in Florida, to determine which enemies perform best.

It’s not easy, and complications abound, Cuda said. For example, some invasive plants were introduced to Florida multiple times, meaning there are multiple genetic variations to identify.

Politics can make it difficult for researchers to visit some foreign countries, or export natural enemies, but the effort is still worthwhile.

Recent success stories from UF include the identification of several beetles and a virus that can control tropical soda apple, which takes over pastureland.

IFAS researchers are investigating classical biological control to manage insect pests, too. One important project is aimed at the Asian citrus psyllid, the insect that spreads bacteria responsible for citrus greening, the most serious disease facing Florida’s citrus industry.