TINY INSECTS PROMISE TO HELP CONTROL BRAZILIAN PEPPERS

mAY 1, 2021

The Brazilian pepper tree (Schinus terebinthifolius) is native to South America. It was introduced to Florida in the mid-1800’s for use as an ornamental plant. Part of the family Anacardiaceae, the pepper tree is related to poison ivy, poison oak, and poison sumac. Levy County is thought to represent the northern edge of the range of Brazilian pepper tree along the Gulf Coast in Florida. It occurs along the East Coast as far north as Sea Islands in southern Georgia. Many native Florida plant communities are invaded and over 700,000 acres in south Florida are now dominated by Brazilian pepper tree. The Florida Exotic Pest Plant Council has classified Brazilian pepper as a Class 1 Exotic, the “worst of the worst” noxious non-native plants with potential for major disruption of natural ecosystems.

            Brazilian peppers produce millions of berries throughout the year that are eaten and distributed widely by birds. The trees grow rapidly up to 20 – 30 feet tall, creating a dense tangled canopy that can shade out native vegetation. 

            Roger McDaniels of the Cedar Key Garden Club started the ‘Pepper Busters’ in 1998. Staff and Friends of the Lower Suwannee and Cedar Keys National Wildlife Refuge along with the Cedar Key Garden Club’s Pepper Busters have been working diligently to rid the area of the hardy, but hated invasive. McDaniels, formerly both a Friends of the Lower Suwannee and Cedar Keys Refuge Board member and President of the Cedar Key Garden Club, wrote the grant application for funding to support invasives eradication. The Refuge purchased safety gear, application equipment, chemicals, and tools for volunteers and staff. Refuge Fire Management Officer, Vic Doig created an invasive plants brochure to inform the visiting public and new residents. The City of Cedar Key, University of Florida, Florida Department of Transportation, Florida Department of Environmental Protection, the Lower Suwannee and Cedar Keys National Wildlife Refuge and the Suwannee River Water Management District have been supportive of this work.

            This year, a number of regular Pepper Busters, now under the leadership of Scott Wright and pepper spotter John Thalacker of Cedar Key, and Vic Doig of the Refuge have been cutting and pulling pepper trees and treating the cut stumps with herbicide to prevent them from growing back.  The Pepper Busters have been working for several hours on Thursday mornings during the cool weather season from November into April. The Busters have been working around Cedar Key, the Lukens Tract part of the Refuge and in the Plantation area on the mainland. It’s hard, dirty work, often in tough brushy and wet places.

            Fortunately, in addition to the hard work of mechanical and chemical control, there is promise that a species of insect from South America can help to control Brazilian pepper in Florida. 

            In 2019, the U.S. Department of Agriculture conducted an exhaustive analysis, review and approval process for biocontrol of Brazilian pepper with a tiny thrips insect from South America, Pseudophilothrips ichini.  Florida’s Department of Agriculture and Consumer Services thrips project team collaborates with researchers at the University of Florida and with members of the USDA’s Agricultural Research Service on release and monitoring of the thrips.

According to UF/IFAS, researchers had to prove the thrips would eat only Brazilian pepper tree and wouldn't pose a threat to the native Florida environment before they could get approval for the release from USDA-APHIS (Animal and Plant Health Inspection Service). Releases began in Broward, St. Lucie, and Collier Counties in 2019.

Sedonia Steininger, Biological Scientist and Daniel Ammann, Laboratory Technician for Florida Department of Agriculture and Consumer Services, Division of Plant Industry visited the Lower Suwannee Refuge on Thursday March 11 this year for an initial release of the tiny thrip insects for biocontrol of Brazilian pepper in this area.  A number of the Pepper Busters attended the release.

In the laboratory, live Brazilian pepper plants are fed to the thrips to keep them alive and to get them to breed. The thrips are collected and placed in transport vials on sprigs of Brazilian pepper and taken to release sites where the sprig is removed from the transport vial and then placed in a wild pepper bush so that the thrips can begin feeding on the wild bush. 

The thrips consume the new growth of the plant as well as flowers and early berries. It is not likely that the thrips will kill a large plant outright but they will impede its growth. The thrips will likely kill the new small plants.  According to Sedonia Steininger, the hard part is growing enough thrips to release.  They are ramping up the culture of the thrips in the laboratory so more will be available to release.  They plan to return to the Lower Suwannee Refuge and to other release sites around Cedar Key to monitor the effects of the thrips on Brazilian peppers, how the introduced thrip populations grow, and how quickly the thrips spread to other pepper plants. We Pepper Busters are excited to see how well this project progresses!        

Pictured here are some photos taken the day of the release of thrips which are part of a Brazilian Pepper control strategy in Florida. The program is a partnership with the U.S. Fish and Wildlife Service and the State Department of Agriculture located on the University of Florida campus.