October 5, 2006
Brazilian Beetle's Appetite Proving Helpful In Destruction Of Invasive Weed
Joint approach allows beetle to munch its way around the Southeast
Florida Agriculture Commissioner Charles H. Bronson announced the successful results of an ongoing biological control program for tropical soda apple (TSA), an invasive plant that has overtaken much of Florida’s natural areas and pasturelands. This program is a cooperative effort between the Florida Department of Agriculture and Consumer Services (FDACS), the United States Department of Agriculture (USDA), and the University of Florida’s Institute of Food and Agricultural Sciences (UF IFAS), and involves rearing and releasing a leaf eating beetle, as well as evaluating other methods for controlling TSA.
Tropical soda apple, an exotic noxious weed native to Brazil and Argentina, has already caused great economic damage to Florida where it has spread to over a million acres, and the majority of Florida counties. TSA is a tall, prickly plant with white flowers and golf ball size fruit whose mottled skin resembles a watermelon. It displaces native plants and is found in hammocks, ditches, groves and vegetable fields. It is a serious problem for ranchers because it quickly covers entire pastures, and cows will eat the TSA fruit, but not the plant. Cattle, one of the main vectors of TSA, spread the seeds from the fruit through their digestive systems to new areas.
“I am very encouraged by the success of this biocontrol program,” Bronson said. “Tropical soda apple has been a serious pest to the cattle industry and Florida’s land managers for many years. Finding solutions to pest problems that are environmentally friendly is an important part of the Department’s mission.”
Since the initial release in 2003 of the South American leaf feeding beetle, Gratiana boliviana, UF IFAS and the USDA have maintained facilities in Florida to rear and release the beetle. In September 2005, FDACS, funded by a grant from the USDA, added to the production effort by establishing two screen houses at the Fort Pierce Farmers’ Market in southeast Florida for rearing and distribution of Gratiana boliviana.
The first release from this facility was conducted in May 2006. Since then, over 16,400 beetles have been released in four counties Hillsborough, Okeechobee, St. Lucie and Martin. These releases were conducted on a variety of TSA affected properties including ranches, conservation lands and residential areas. Eight weeks after release, many areas have active beetle populations that have moved beyond the initial release sites. The Fort Pierce operation increases the number of beetles available for release throughout Florida, including the possibility of fulfilling requests from interested individuals to release the insects on their TSA infected properties.
The leaf feeding beetle, which is host specific to TSA, damages the plant extensively, stops fruit/seed production, and weakens the plant so other diseases can easily infect tropical soda apple. Biological control is a cost effective way to manage TSA in natural habitats that are not easily accessible by other management methods. The beetle will spread from its original release site, allowing for large coverage areas. Beetles have been found up to 10 miles from their release site.
The biocontrol program is one tool used in an effort to control TSA. The current primary treatment options for controlling TSA include herbicide application and mowing the plants before they produce fruit. Other ongoing research activities include studying additional leaf eating beetle species, plant viruses that attack TSA, and a bioherbicide that kills the invasive plant.
For information about tropical soda apple, the leaf eating beetle, or participation in the release program, call 1-888-397-1517 or visit www.doacs.state.fl.us/pi/
For more information:
Denise Feiber
(352) 372 3505 x102
feiberd@doacs.state.fl.us
