Home » Weevils not stopping salvinia in Lake Bistineau

Weevils not stopping salvinia in Lake Bistineau

by Minden Press-Herald

Giant salvinia on Lake Bistineau isn’t disappearing at a rate which had been hoped for by agencies and individuals involved in eradication attempts, but the battle against the aquatic growth continues on a daily basis.

Members of the Bistineau Task Force heard Thursday that different techniques are still being used, including one which has introduced millions of tiny combatants onto the floating mats of the vegetation. Unfortunately, little progress has been seen, said one of the men involved in the eradication programs.

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“Since 2007, more than two million (salvinia) weevils have been introduced into the lake. We’ve done quite a bit with weevils, but we’ve seen no practical results,” Jeff Sibley, biologist with the Louisiana Department of Wildlife and Fisheries, said.

Earlier in the meeting, Lee Eisenberg said chemical treatment is still the prime means of trying to control the salvinia, but noted that interest in the weevils is increasing. In 2012, Eisenberg was raising salvinia weevils at Caddo Lake for Texas A&M University.

Currently, he works as a contractor for The Greater Caddo Lake Association in Uncertain, Texas, a group which has an interest in biological control of giant salvinia.

“Last summer, we had between 6,000 and 7,000 acres of giant salvinia. That means many recreational opportunities are gone, such as hunting, fishing and boating,” he said.

One disadvantage of using weevils to fight salvinia is the climate in northwest Louisiana, Eisenberg said.

“The weather here isn’t really conducive for the best use of weevils. They thrive more in tropical conditions,” he said. “But we’re going to keep adding to them and we fully expect to have something to show next fall.”

Sibley said weevils have been spread on the upper end of Lake Bistineau “…in close spots where the timber is thick, we’ve put them in close quarters and we’ve scattered them. None have shown a difference in results.”

Like Eisenberg, Sibley acknowledges the weevils face a disadvantage in this area.

“This is a tropical insect, we are in a temperate zone,” he said. “We keep hitting roadblocks with winter temperatures. We have another event, we have to start over again.”

Despite the occasional setback, Sibley said the effort to control and eliminate salvinia goes on.

“We don’t have all the answers, but we’re working on it. We research with the Corps of Engineers, LSU and the LSU Ag Center,” he said.

Sibley told BTF board members the gates on Lake Bistineau have been closed (Thursday). If the water flow stays as it is now, the lake could be filled in a couple of weeks, he said.

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