The Louisiana Department of Wildlife and Fisheries joined efforts with Lake Bistineau property owners and other concerned citizens this past Saturday to distribute over 110,000 giant salvinia weevils throughout the lake to help combat the growth of the invasive plant. Distribution efforts targeted isolated areas of the lake that do not dewater and are disconnected from the main lake.
Sixty seven area residents volunteered by distributing weevil and larvae-infested plant material in areas near their property that hold water during lake drawdowns. Through volunteer labor alone, 102,000 adult weevils were stocked into the lake. LDWF personnel added an additional 8,400 insects to the total count.
“This is the kind of community commitment that will help us in our battle to control salvinia on this beautiful lake,” LDWF Secretary Jack Montoucet said. “In my conversations with lake residents, they pledged to play a role in the fight. They proved it, and I applaud them. We are committed to continuing these types of cooperative efforts.”
Weevils are a natural enemy of giant salvinia in its native habitat and can serve to limit the growth of the plant. They only feed and reproduce on giant salvinia, and if established, can serve as a long-term biological control for the plant. The weevils for this particular effort were harvested from Iatt Lake in Grant Parish, where they are found in high densities and have survived two successive winters, increasing their likelihood of survival in the north Louisiana climate.
This stocking is an ongoing effort by the department to establish a weevil population on Lake Bistineau. Weevils were first stocked in 2007. Following this stocking biologists will continue to monitor the lake for the presence of weevils. If successfully established, it is likely to be 2 to 3 years before any long-term results are visible.
The department will continue to collaborate with LSU AgCenter researchers to identify and evaluate new potential giant salvinia control techniques. Recent efforts have focused on identifying a population of giant salvinia weevils that can survive winter temperatures in north Louisiana.
LDWF uses an integrated management program of water level fluctuations, herbicide applications, and biological control measures to achieve combined benefits. This approach is designed to reduce vegetation levels while maximizing recreational use of Lake Bistineau for the public throughout the year.