IPRL results from Salvinia molesta and Salvinia minima.

Salvinia weevil (Cyrtobagous salviniae)

Two ecotypes of this species are known in the US. The smaller Florida ecotype was likely introduced accidentally to FL along with common salvinia prior to 1960, and it spread naturally to giant salvinia in FL. This ecotype was subsequently intentionally redistributed to common salvinia in LA beginning in 2002 and to giant salvinia in LA and TX in 1999. The larger Brazilian ecotype was intentionally released in Australia and from there redistributed to giant salvinia in LA and TX from 2001. 

no biological control

biological control present

For more details please reference link to a publication below:

Suppression of Salvinia molesta Mitchell in Texas and Louisiana by Cyrtobagous salviniae

Weevils Versus No Weevils: A Comparison of Salvinia minima Populations in Florida and Louisiana

Field Guide for the Biological Control of Weeds in Eastern North America/Salvinia