(05/10/19) BATON ROUGE, La. — Giant salvinia has been a major problem on bodies of water in Louisiana for more than a decade. It is now causing a problem in Puerto Rico, and officials there are leaning on Louisiana’s experience in fighting this invasive weed.

Scientists with the LSU AgCenter have been engaged in developing a comprehensive management plan for salvinia control. The weed, which is native to South America, has now overtaken Lago Las Curias, a lake southeast of San Juan. A private citizen, Daniel Diaz, who lives on the lake, began doing research on control efforts, and he contacted the AgCenter based on his research.

AgCenter entomologist Rodrigo Diaz is participating in a project that raises a weevil that feeds on the salvinia and causes the plant to die.

“Puerto Rico has a tropical climate, and biological control would be a great option there,” Diaz said.

The plan calls for weevils raised in Louisiana to be transported to Puerto Rico and then released into the salvinia-infested lake.

Officials with the AgCenter and the University of Puerto Rico are working on securing the necessary permits to export the weevils from Louisiana to Puerto Rico.

Jose Carlos Verle Rodrigues, an entomologist with the University of Puerto Rico, is helping with getting the permits there.

Charlie Wahl, an AgCenter entomology research associate, will be responsible for bringing the weevils to the island once approval is gained. He has extensive experience in rearing and releasing the weevils in Louisiana and monitoring their effect on salvinia.

“The weevils have been effective in controlling giant salvinia,” Wahl said. “One of the hurdles with the weevils in Louisiana is their ability to survive cold temperatures, like we had during January 2018. That shouldn’t be a problem in Puerto Rico.”

Wahl said there is a strategy for placing the weevil, and he will help show how to use the weevils to their maximum effectiveness.

Diaz said there is a need to help the recovery of freshwater habitat on the island, which is still feeling the effects of Hurricane Maria.

“There are not many resources available to help fight this infestation because of the recovery efforts,” Diaz said. “We can share our experience in developing a plan to manage giant salvinia and other aquatic weeds.”

Giant salvinia has overtaken Lago Las Curias, an inland lake southeast of San Juan, Puerto Rico. The salvinia is so thick it is suppressing the growth of other plants. Scientists with the LSU AgCenter are collaborating with scientists at the University of Puerto Rico to begin a biological control effort using weevils raised by the AgCenter in Louisiana. Photo by Daniel Diaz

Lago Las Curias, an inland lake southeast of San Juan, Puerto Rico, is covered with the giant salvinia, an invasive aquatic weed native to South America. Giant salvinia is a problem in Louisiana, and LSU AgCenter scientists are engaged in a biocontrol effort using a weevil that eats and kills the plant. The AgCenter is working with scientists at the University of Puerto Rico to start a similar effort on the island. Photo by Daniel Diaz