Generous Residents Give Salvinia-eating Weevils New Home

Giant salvinia has been a big problem at Lake Bistineau. Pretty soon, a solution will be introduced to the lake...salvinia-eating weevils.

Thanks to the generosity of some folks who live on the lake, the weevils have a place to stay. During Thursday's Bossier Parish Police Jury meeting, two people donated greenhouses to help accommodate the tiny bugs.

"We're ready to put plastic over the top," said Bistineau Task Force member-at-large Pete Camp in a news release. "People really came together to make this happen. We will have our own weevils coming from the greenhouse in the next two to three weeks."

According to the news release, another Lake Bistineau property owner, who had purchased a Shreveport nursery, donated a pair of greenhouses, each measuring 30 x 80 feet. Camp said some dirt work would be necessary to set the pair, but a local construction company is donating heavy equipment and operators to get the job done.

"We're going to build a boat ramp on the property," Camp said. "Once that is done, we will have more greenhouse space than at Caddo Lake, we will be closer to the water and have our own boat ramp. We will be a state-of-the-art facility in the next few months."

There's no word so far, though, on when the new batch of weevils will be released into the lake.

"In winter, all you try to do is keep them alive. We want to be ready to put them in the lake in early spring, when the water gets above 65 degrees," said Camp. "We want to start establishing our weevils and not have to transport them."

What is salvinia?

According to the Texas A&M Agrilife Extension website, Giant salvinia is native to South America. It is a small free-floating plant that grows in clusters and develops into dense, floating mats or colonies in quiet water, undisturbed by wave action. The floating leaves of giant salvinia are oblong (0.5 to 1.5 inches long) with a distinct midrib along which the leaf may fold forming a compressed chain-like appearance.

Salvinias have stiff leaf hairs on the upper surface of the leaves. In giant salvinia the leaf hairs have a single stalk that divides into four branches that reconnect at the tip, giving the hair a cage-like or egg-beater appearance. Underwater the leaves are modified into small root-like structures. The entire plant is only about 1 to 2 inch in depth. Salvinias are ferns and have no flower.

Giant salvinia can double in size in 4 to 10 days under good conditions. Giant salvinia is an aggressive invader species. If colonies of giant salvinia cover the surface of the water, then oxygen depletions and fish kills can occur. These plants should be controlled.

Dense salvinia colonies provide Habitat for micro invertebrates but if salvinia completely covers the surface of a pond it will cause oxygen depletions. These colonies will also eliminate submerged plants by blocking sunlight penetration. Salvinias have no known direct food value to wildlife and is considered an exotic and highly undesirable species.

What are weevils?

From Wikipedia: A weevil is a type of beetle from the Curculionoidea superfamily. They are usually small, less than 6 mm (0.24 in), and herbivorous. Over 60,000 species are in several families, mostly in the family Curculionidae (the true weevils). Some other beetles, although not closely related, bear the name "weevil", such as the biscuit weevil (Stegobium paniceum), which belongs to the family Anobiidae.

Many weevils are damaging to crops. The grain or wheat weevil (Sitophilus granarius) damages stored grain. The boll weevil (Anthonomus grandis) attacks cotton crops. It lays its eggs inside cotton bolls, and the larvae eat their way out.

One species of weevil, Austroplatypus incompertus, exhibits eusociality, one of the few organisms outside the Hymenoptera to do so.