Send In The Bugs! Brazilian Thrips Released To Fight Invasive Peppertree



Scientists from the University of Florida are betting on a tiny (.08 to .12 inches) winged insect to help protect the Florida Everglades. Why? Because the insects, Brazilian peppertree thrips, may be our best hope against combatting invasive Brazilian peppertree, which currently infests over 700,000 acres in Florida, including many sensitive habitats such as mangroves and sawgrass marshes in the Everglades. Introduced to Florida as an ornamental in the late 1800s, Brazilian peppertree is overtaking agricultural and natural areas of Florida, Hawaii, and Texas. A relative of poison ivy, it can cause allergic reactions in people and toxic effects when ingested by birds or animals.

Brazilian peppertree.

Despite the expenditure of millions of dollars, traditional methods have been unable to stem the spread of this weed. Between 2010 and 2011, the Florida Fish and Wildlife Conservation Commission (FWC) spent $7 million in herbicidal controls. In 2011, the South Florida Water Management District spent $1.7 million to control Brazilian peppertree. (These budgets would have been larger if resources permitted.) While these control efforts continue, federal, state, and local land managers have been waiting for better options.

For about 30 years, scientists searched for the right bug or combination of insects for a less-intrusive way to mitigate Brazilian pepper trees. Eventually, it was found the thrips, called Pseudophilothrips ichini, and a leaf galler, Calophya latiforceps, appeared to effectively consume the peppertree. To gain approval from the USDA Animal and Plant Health Inspection Service (APHIS) for release as a biological control agent, the insects first had to undergo rigorous testing by researchers to ensure they would not harm native organisms. UF/IFAS, the USDA, and FDACS scientists had been working on this research project since 2009, bringing the insects to quarantine laboratories at the UF/IFAS Indian River Research and Education Center and the USDA facility in Fort Lauderdale.

Plans are to release yellow Brazilian peppertree leaf gallers next year as well.

This past July, the thrips were released for the first time. The second release took place late last month at Adams Ranch in Fort Pierce, FL. Researchers plan to give the beneficial insects to residents if they prove effective in tests on publicly owned lands. Next year, in phase two, they’ll put the insects into more publicly owned lands and on large ranches in South Florida. The yellow Brazilian peppertree leaf galler has also been approved for release, which is expected to happen in 2020. In the third year, scientists plan to let the insects loose in residential areas. But results will not be immediate. Since it takes several years for an organism to establish and affect the invasive plant, scientists expect to see a reduction of Brazilian Peppertree leaf cover and bud growth over the next 15 years. For more information, visit here.