University of Florida to release biocontrol against Florida’s most serious invasive Brazilian peppertree

Mike Adams spends $250,000 every year to manage Brazilian peppertrees spread over the 40,000-acre ranch where his family has developed the Braford breed of cattle since 1937. Adams recounts years when the invasive tree from South America overtook natural areas on the ranch, pushing out pasture and grasslands.


But a tiny insect is about to become a game changer for his property. Scientists from University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) will release the first biological control insect, the Brazilian peppertree thrips, or Pseudophilothrips ichini, against the problematic tree at Adams Ranch on Thursday, Oct. 24, from 10 a.m. to noon. The scientists and Ken Pruitt, who as president of the Florida Senate championed appropriations to begin local biocontrol research, invite the public to join them for the Peppertree Biocontrol Release Celebration as they free the thrips onto live Brazilian peppertrees. Adams Ranch is located at 26003 Orange Ave, or State Road 68, west of Fort Pierce. The event and parking are free.

“It’s going to be a win-win for us and the environment,” said Adams. “The university’s biocontrol program will help us to protect our natural areas, help our cattle to have more grass, and we won’t have to apply chemicals to trees anymore.”

Former Florida Senate President Ken Pruitt to Speak

Leading the celebration will be a keynote address by former State Senator Ken Pruitt. UF/IFAS officials and scientists who have made contributions to 30 years of research culminating to the biocontrol release will be present.

The thrips has been under research for more than 10 years at the University of Florida’s Norman C. Hayslip Biological Control Research and Containment Laboratory, 13 miles east of Adams Ranch. The lab, completed in 2004, is located at the UF/IFAS Indian River Research and Education Center (IRREC) in Fort Pierce.

Two conservation agencies alone spend $4.7 million annually to control Brazilian peppertree

Adams said his family members have had to manage Brazilian peppertree for more than 80 years. The tree is the state’s most serious invasive weed, which costs the Florida Fish and Wildlife Conservation Commission and the South Florida Water Management District over $4.7 million every year to control. Today, more than 700,000 of Florida’s natural areas, ranchlands and highway roadsides are consumed by the trees. The densest infestations are in the Florida Everglades, according to Ronald Cave, director of IRREC.

“University of Florida researchers work as a team to study and gain approval for the release of specialized insects that will manage the invasive Brazilian peppertree,” said Cave. “Over time, the thrips, in addition to three more insects that will be released to reduce Brazilian peppertree, will decrease the need for land managers and ranch owners to use heavy machines and toxic chemicals to remove the invasive tree.”

Brazilian peppertree encroachment

Carey Minteer, assistant professor and invasive plant research leader at the UF/IFAS Hayslip Lab, said Brazilian peppertree disrupts our ecosystem by outcompeting our native plants and reducing habitat for native wildlife. Minteer works with the Brazilian peppertree thrips and with a second biocontrol insect, the yellow Brazilian peppertree leaf galler, or Calophya latiforceps. The leaf galler gained approval for distribution as well and will be mass-reared for release at a later time.

“The biological control agents approved for release have been under study for over a decade and were deemed safe by federal and state scientific authorities. These insects feed and reproduce only on Brazilian peppertree,” Minteer said. Officials with the U.S. Department of Agriculture (USDA) and Animal and Plant Health Inspection Service, or APHIS, ensure insect biocontrols are safe to release.

Work at the local UF/IFAS facility began over 17 years ago, but preliminary research began in the late 1980s, by now-retired UF/IFAS entomology and nematology professors, Frederick “Fred” Bennett and the late Dale Habeck. Bennett and Habeck’s tasks were overseas exploration, or searches for insects that feed on Brazilian peppertree in its native range in South America.

“The tree is much smaller in its natural habitat and does not reproduce as it does in the U.S,” said Jim Cuda, professor of entomology and nematology and Fulbright Scholar at the UF Gainesville location. Cuda’s entire career, which began as an assistant research professor in 1998, is devoted to the study of Brazilian peppertree.

Biological control successes throughout Florida

“Florida has a long and storied history of weed biological control success stories, beginning with alligator weed in the 1960s,” said Cuda. “Brazilian peppertree will undoubtedly be added to that list.”

Cuda said he has been fortunate to work on the Brazilian peppertree biological control project; he compares the endeavor to a relay race. Research began with Bennett and Habeck, who identified the thrips as a potential biological control agent. Then, Habeck and a new UF/IFAS scientist, Julio Medal, conducted the preliminary screening studies. Cuda and his technician, Judy Gillmore, developed the first mass rearing procedure for the thrips and completed the initial testing.

To perform host range studies for Florida’s Brazilian peppertrees, Veronica Manrique, a former Hayslip Lab postdoctoral researcher, worked with USDA scientists to determine the thrips’ candidacy as a biocontrol agent to Florida’s trees. Approved for release in June 2019, the first distribution of thrips took place on July 16, 2019, in Davie. More thrips have been released in Miami-Dade, St. Lucie, Brevard, Collier, Hillsborough, Sarasota and Polk counties, said Minteer.

Scientists at the Hayslip Lab have gained approval for a second biocontrol known as the leaf galler. The yellow Brazilian peppertree leaf galler was discovered in South America in 2010 by former UF/IFAS graduate student, Lindsey Christ, and postdoctoral researcher, Rodrigo Diaz, explains Cuda. “Research on the biology and host range of the leaf galler was completed by Diaz and his mentor, William ‘Bill’ Overholt.”

Overholt is an emeritus professor of entomology and nematology. He preceded Minteer’s position at the UF/IFAS Hayslip Lab. Minteer said the Brazilian peppertree thrips is the first weed biocontrol agent to be released from the lab. The second biocontrol insect, the yellow Brazilian peppertree leaf galler, will be released in the next few months, she added.

In the next year, the two insects will be mass-reared at the UF/IFAS Hayslip lab and distributed to land managers who will complete the work to control Brazilian peppertree in Florida, said Minteer.

“It is the willingness of local citizens to take part in the distribution of the biocontrol insects that is vital in the fight to control Brazilian peppertree. I welcome them to join us at Adams Ranch on October 24.


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Posted: October 17, 2019

Category: Horticulture, Invasive Species, Natural Resources, Pests & Disease, UF/IFAS, UF/IFAS Research

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