Salvinia molesta (giant salvinia), a Federally Listed Noxious Weed, has been located in a stormwater pond in Jacksonville between St. Augustine Road and Phillips Highway.
The invasive plant has caused problems in six water bodies in Florida over the last decade but has recently been discovered in Duval for the first time.
Giant Salvinia forms dense mats that shade out native plants lowering the biodiversity. Mats get thick enough to reduce dissolved oxygen which can kill fish and they create ideal breeding environments for mosquitoes.
City of Jacksonville contractors that were treating the pond reported it to FWC who are working with the Army Corps of Engineers and the city to address this high priority.
It is not known how many areas are affected or if the plants have been spread from the current pond to other ponds either by equipment or waterfowl.
Army Corps biologists visited the site and noted the plants had gone into the drainage pipes for the pond that flows into Craig Creek, which empties into the St. Johns River.
There is concern that it may have gotten into the river already where it could spread quickly.
It multiplies when it is cut up or breaks apart. It looks like duckweed with two round leaves but the leaves start to curl up like lettuce as the plant matures. It thrives in shallow water without much current.
The only methods to combat the spread are with herbicides and control with biological wevils.
According to The First Coast Invasive Working Group, The City of Jacksonville, contractors manage over 250 stormwater ponds throughout the Jacksonville area, so it could have been spread to other ponds on equipment.
The task force is urging everyone to be on the lookout for this plant and to report it if you see it.
Take pictures, report them in Invasive Species Mapping Handbook or call/email Jessica Spencer (904-318-9110, Jessica.e.spencer@usace.army.mil) or Kaitlyn Dietz (904-380-8623, Kaitlyn.Dietz@floridadep.gov).
Additional information on how to properly identify the species and the risks it poses to the state of Florida can be found at the following links:
https://www.eddmaps.org/distribution/viewmap.cfm?sub=2785
https://plants.ifas.ufl.edu/site/assets/files/1173/invasiveplants_giantsalvinia.pdf
https://plants.ifas.ufl.edu/plant-directory/salvinia-molesta/
https://plants.ifas.ufl.edu/site/assets/files/1173/salmol.pdf
