African Weed Is Choking Lakes in South : Environment: Hydrilla ensnares swimmers, fouls boat propellers, clogs power plants, crowds out large fish. It has been blamed for drownings.

First there was kudzu, which cloaked much of the land in the South with its tenacious tentacles. Now, a rampant weed described as kudzu’s aquatic cousin is clogging Southern lakes.

The weed, hydrilla, has been ensnaring swimmers, fouling boat propellers and clogging up power plants from Florida to the Carolinas.

Hydrilla propagates by tuber-like buds that winter in lake beds and sprout in spring, growing from depths of about 17 feet or less.

“It’s pretty serious. It’s covered the whole lake,” said Jodie Pack, owner of a marina on the 110,000-acre Lake Marion, where hydrilla was discovered in South Carolina in 1982.

The tentacular water plant is believed to have found its way across the Atlantic from Africa through the aquarium trade. The weed invaded Florida in the 1950s but only began to pose a serious environmental threat in the 1960s and 1970s as boating became a popular American pastime.

Hurricane Hugo hastened the plant’s progress, blowing it across South Carolina and North Carolina in 1989.

Hydrilla is known to infest 52 lakes in North Carolina, 35 in the Raleigh area. It lurks unsuspected in an untold number of others, according to state aquatic weed controller David DeMont.

“Once it’s established, it quickly takes over,” DeMont said. “In Florida, in particular, hydrilla has actually been blamed for several drownings.”

In South Carolina, the weed shut down the St. Stephen Power House on May 29. The dam, on the Rediversion Canal off Lake Moultrie, has operated only erratically since.

“It can run for an hour and a half or so and then it becomes clogged up again,” said Willard Strong, spokesman for Santee Cooper, South Carolina’s state-owned power company.

At Alabama’s hydroelectric plant in Guntersville, the Tennessee Valley Authority is trying to curb hydrilla by spraying and lowering water levels, plant operator Robert Hunt said.

In the absence of a permanent solution to the problem, officials are concentrating on controlling the plant’s growth and educating its main ally--people. The weed pond-hops primarily by traveling on boat propellers, to which it tenaciously clings.

South Carolina has posted signs at boat ramps, warning people to clean their propellers.

Fishermen have been blamed for spreading the plant intentionally, hoping to improve their catch. Although hydrilla crowds out larger species of fish, it provides protection for small fry, DeMont said.

Chinese grass carp, genetically manipulated to be sterile, find the weed tasty. But, at $6 to $8 a head and with 10 to 20 carp needed per infested acre, the solution can be costly.

South Carolina is spending nearly $1 million this year on hydrilla control. The state already has dumped 300,000 carp into Lake Marion and is considering adding 100,000 in the largest effort of its kind in the country, said Danny Johnson, South Carolina’s surface water director. Nearby Lake Moultrie, about 60,000 acres, also is infested.

“If you were going to design a good place for hydrilla to grow, it’s hard to do better than those two lakes,” Johnson said.

Lake Gaston is the largest North Carolina lake with hydrilla; it has spread from 30 to 200 acres in two years.

“It’s spreading rapidly in that lake and there’s a lot of local concern about it,” DeMont said.

With property values declining along affected lakes, state legislatures are getting into the act. North Carolina legislators this year enacted laws to prohibit the culture and sale of hydrilla, which is used in aquariums.