Title: USA researchers testing natural herbicide to fight giant salvinia & water hyacinth
[thenewstar.com, by Stephen Largen: December 13, 2009] Louisiana Tech University researchers are testing a naturally occurring microorganism that acts as a natural herbicide against a pair of nuisance aquatic plants that are increasingly overtaking the state’s lakes and waterways. As the state prepares to face a new year that will almost assuredly bring unprecedented growth of giant salvinia and water hyacinth, two exotic, invasive plants that can double in biomass every three days under ideal conditions during the summer, the research offers some hope for the budget-crunched state Department of Wildlife and Fisheries.
Giant salvinia and water hyacinth can block all sunlight penetration into bodies of water, altering entire ecosystems. “It’s definitely the No. 1 weed problem,” said Evan Thames, Wildlife and Fisheries biologist manager for District 4. “And it will overrun us if we can’t control it.”
An effective herbicide to combat giant salvinia and water hyacinth already exists. Last summer and fall, LDWF used a new chemical, Galleon, to help clear 750 acres of the aquatic plants on Turkey Creek in Franklin Parish. Galleon is highly effective and can cover 48 acres of water per gallon. There’s just one problem: The chemical costs $1,851.50 per gallon, a steep price for LDWF.
There are 730,000 acres of public water bodies with aquatic vegetation problems; LDWF’s slightly more than $8 million spraying budget for this fiscal year will allow LDWF to treat only about 37,000 acres.
The high cost of Galleon is the main reason LDWF officials hope Tech’s microorganism proves effective in pilot-level studies this summer.
Lynn Walker, a professor of biological sciences at Tech, is leading the research. He said his research team is not announcing the name of the microorganism, which he said can be found in northeastern Louisiana, because they hope to secure a patent for the university for a herbicide using the microorganism.
Small-scale testing at Lake Bistineau last summer proved effective. Research results indicate that the microbe can be grown under laboratory conditions and then sprayed onto the foliage of giant salvinia.
Walker said the unit price of the herbicide would likely be much less than Galleon. Tech hopes to secure the patent and then draw interest from commercial companies, who would pay a licensing fee and develop a product for mass sale. Walker and researchers plan to test the microorganism on a wider scale next year.
There’s no timeline for when a product could hit the market, but its arrival can’t come soon enough.Giant salvinia and water hyacinth nearly overran several water bodies in the state during the last two years, including Bistineau. Cold weather this winter is not expected to be enough to kill the plants that remain in the waters from last year.
“Based on what we saw last year, there’s going to be a lot of residual plants that will be ready to resume growing,” Walker said, “It really takes a lot to kill this stuff.”
In the meantime, LDWF is attempting to breed and propagate a weevil that can naturally control the nuisance plants. Weevils control giant salvinia in South America, LDWF Secretary Robert Barham said. LDWF has been trying to breed the weevil for several years. “I hope the research at Tech finds the silver bullet,” Barham said. “I’ll be the biggest Bulldog you can find if it does.”