LAKE COUNTY — Boat crews with the California Department of Food and Agriculture (CDFA) found a mass of hydrilla plants among tulle weeds in Clear Lake Wednesday morning, the first major find of the invasive aquatic weed this year.
Agricultural technician Russ Huber said he and his fellow crewmembers were still determining how much area the weeds covered at a point approximately one and a half miles west of the Clear Lake State Park boat ramp. Huber said because the invasive weeds are growing among a dense swathe of tulles in the area that is more than 40 feet wide, the CDFA may have to use a helicopter to eradicate them.
“It”s just about the only way to get to them,” Huber said. He said he and his men will have to walk in the three-foot deep water starting today to determine exactly where the weeds are. He said the packs of copper used to kill the plants on contact are heavy and carrying them on foot in the three-foot-deep water would be impractical.
“It”s a very invasive and aggressive weed that can overtake a lake very rapidly, as it has in the eastern part of the United States, and in Florida, for example,” Lake County Deputy Public Works Director Bob Lossius said.
Lossius said the state”s approach is to eradicate the weed, not to manage or control it. Akers said Florida spends approximately $30 million annually just controlling the weed.
“My experience with it is that in Florida, it gets so thick that you have to mow it in order to allow boats to pass through,” Lossius said.
The quick-spreading weed comes from Africa, and can grow dense enough to cover a water body”s surface. It can clog water intake valves and ensnare watercraft because of its density.
Last year, 28 plants were found covering more than 50 acres in the Soda Bay area on Clear Lake, according to Huber.
The CDFA has battled the hydrilla plant on Clear Lake since 1994, according to CDFA scientist Patrick Akers. He said the agency sprays a copper compound called Komeen on the water”s surface where the weeds are found. Four to six days later, the CDFA distributes pellets of the herbicide fluridone, known by the trade name Sonar.
Akers said the pellets settle in the sediment layer on the lake bottom, where hydrilla tubers no bigger than a navy bean lay in wait for five to seven years for the right conditions to sprout into new plants.
Contact Tiffany Revelle at trevelle@record-bee.com.
