Hutchison applauds fight against invasive species on Texas lakes

KARNACK– U.S. Sen. Kay Bailey Hutchison told a group gathered Aug. 10 at Caddo Lake National Wildlife Refuge near Karnack that invasive species such as the giant salvinia are a threat to the refuge.

“While Caddo Lake is home to hundreds of animal, fish and plant species, invasive species threaten this magnificent resource,” said Hutchison. “We are proud to work with the Caddo Lake Institute and Texas A&M University on creating a center of excellence focused on eradicating invasive species.”

Hutchison’s remarks were preceded by a tour of the Center for Invasive Species Eradication’s salvinia weevil-rearing facility located at the wildlife refuge.

The center was developed through support from Hutchison and is funded by Congress through the U.S. Department of Agriculture’s Natural Resources Conservation Service. It is administered by Texas AgriLife Research and the Texas AgriLife Extension Service and managed by the Texas Water Resources Institute.

Giant salvinia is a free-floating aquatic fern that has aggressively invaded Caddo Lake and other lakes in Texas. Since its appearance on Caddo Lake in 2006, giant salvinia has been an aggressive invader that can double in size in four to 10 days under favorable growing conditions.

In the center’s first project, AgriLife Research and AgriLife Extension scientists are evaluating and demonstrating multiple control methods—biological and chemical—and assessing their effectiveness in killing giant salvinia, according to Lucas Gregory, the center’s project manager.

The salvinia weevil is the plant’s only biological enemy, according to the researchers. Scientists are raising the tropical weevil at the rearing facility to supply weevils for release on Caddo Lake and to serve as a living weevil laboratory, Gregory said.

“We have released more than 100,000 weevils and 300,000 weevil larvae at four locations on the lake, to date and will be releasing more this afternoon,” he said.

Gregory said the scientists are also evaluating several new herbicides to determine their effectiveness in controlling giant salvinia.

“We plan to begin large-scale chemical treatments in late August using proven chemicals and hope to treat upwards of 300 acres,” he said.

Other plans include collaborating with USDA’s Agricultural Research Service’s Biological Control Lab in Argentina to obtain cold-tolerant weevils to see if they fare better in Caddo Lake and establishing a weevil nursery in the upper portions of the lake that will naturally disperse during flooding.

Scientists involved in the project are Dr. Allen Knutson, AgriLife Extension entomologist; Dr. Michael Masser, AgriLife Extension fisheries specialist; Dr. Paul Baumann, AgriLife Extension weed specialist; Howard Elder, Texas Parks and Wildlife Department aquatic habitat biologist; and Patrick Ireland, AgriLife Extension assistant and project coordinator for the center.

Collaborators include the Caddo Lake Institute, Caddo National Wildlife Refuge, Cypress Valley Navigation District, Texas Parks and Wildlife Department, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, Natural Resources Conservation Service, Cypress Valley Navigation District, Louisiana Department of Wildlife and Fisheries, and Louisiana State University.

More information is available at http://cise.tamu.edu .

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