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Invasive flatworm has arrived

By Staff | Aug 10, 2016

This New Guinea flatworm was captured on Sanibel in September 2015. Photo by SCCF

The New Guinea flatworm, identified as one of the 100 worst invasive species due to its impact on biodiversity, has been found on Sanibel.

The Platydemus manokwari, was positively identified on Sanibel Island, after City of Sanibel Natural Resources’ Joel Caouette discovered a flatworm on property owned by the Sanibel-Captiva Conservation Foundation back in September 2015.

After sending what was then an unknown flatworm to Florida International University, it was positively identified as the pesky New Guinea flatworm.

“There has only been one New Guinea flatworm found on Sanibel, that I am aware of,” Caouette said. “It is such a concern because the flatworm is such a voracious eater and they mainly feed on adult tree snails and their eggs, as well as earthworms in the soil.”

Most recently, reports of New Guinea flatworms have also been found in Cape Coral.

The New Guinea flatworm is one of the most dangerous invasive species in the world, and unfortunately has landed in Florida, including one on Sanibel in September of 2015. Photo by Shinji Sugiura, Google Images

The introduction of the flatworm in an environment can eventually endanger such important species as snails as earthworms, which are important to agriculture.

The flatworm is native to New Guinea and other South Pacific Islands. It started its invasive trek in 1962 in Queensland, Australia and now has been identified worldwide, inhabiting tropical climate zones.

“It does well in every temperate tropical climate,” Caouette said. “They are mainly found in the soil or under rocks or plants.”

The flatworm was first discovered in the U.S. in South Florida. One way they spread is by hitching a ride on plants which are sold to consumers, such as potted plants and trees.

“It is a good idea to check your plants, under the leaves and in the soil,” Caouette said. “That’s one of the best ways to prevent the spread of the flatworms.”

Another negative impact flatworms pose is that they are known vectors for parasitic nematode, also known as rat lungworm, which can be spread to humans via rats.

If a flatworm is found, do not touch it and if you do, wash your hands immediately. The flatworms are coated in an acidic slime and the best way to kill them is by pouring boiling water on them.

But positive identification is important, so not to harm native species mistakenly identified as a New Guinea flatworm.

A New Guinea flatworm has leech-like similarities, is flat and dark brown with a thin light stripe down the middle of it.

But before exterminating a flatworm, or if there are suspicions that it is the invasive specie, take a picture of it. It should be reported to the City of Sanibel Natural Resources Department at (239) 472-3700 or to the Florida Fish and Wildlife Conservation Commission at 888-IVE-GOT1 (888-483-4681).