Updated

As Donald Trump and Hillary Clinton fight to win Florida hearts and minds with promises to combat Zika and jolt the economy, residents in the vital battleground say the candidates need to focus on another pressing problem – one that’s flown under the national radar – to earn their votes: Algae.

A slimy, blue-green algae bloom -- described as “watery guacamole” by some Floridians -- emerged this spring in Lake Okeechobee and within weeks had seeped into lagoons, rivers and other coastal waterways.

The bloom has grown to pose a major health and economic problem. And for presidential candidates courting Florida voters, it’s a curveball forcing them to come up with a response plan.

“I think the candidates need to do more. It’s all about the economy,” said Bonnie Creber, owner of the Coral Reef Motel in Jensen Beach, Fla., one of many locales affected.

Clinton and Trump have addressed the politically charged issue on the campaign trail and this week pledged their interest in finding a solution.

“Mr. Trump has spoken about this on recent campaign stops in Florida and remains very supportive of Governor Rick Scott and all he is doing to combat the issue,” spokeswoman Hope Hicks said Wednesday.

Clinton informed local officials earlier this week that former EPA Administrator Carol Browner will visit the region Monday on her behalf, according to a letter the campaign provided to FoxNews.com.

“Following her trip … she and I will connect to discuss what next steps we can take to best serve the Treasure Coast,” Clinton wrote. “Like you, I believe that clean water is not a luxury -- it’s a fundamental right. I am committed to finding a long-term solution to this problem.”

The candidates have some catching up to do. Florida Republican Gov. Rick Scott in June declared a regional state of emergency to allow the state and local governments in south Florida to “take swift action to mitigate the spread.” In July, he asked President Obama for emergency funding.

But the thick, smelly bloom by then already had moved into the Atlantic Ocean, killing plants and marine life while threatening the state's vital tourism and fishing industries. It also has been associated with respiratory and skin problems.

“They had to close the beaches on Fourth of July weekend. And on the Treasure Coast, it’s all about the water, sailing, fishing and swimming,” Creber told FoxNews.com.

Trump addressed the issue at a Florida stop in late July but so far has not announced whether he’s accepted an offer from the Martin County commissioners to see the bloom, as Clinton’s campaign has.

Mahen Gunaratna, a spokesman for Clinton's Florida campaign, told FoxNews.com on Thursday: "Hillary Clinton understands that clean water is a basic right of all Americans, and that's why she's been vocal on the need for a long-term solution to the toxic algae bloom."

Clinton also wrote an Aug. 17 column for Treasure Coast Newspapers addressing the outbreak as part of Florida’s larger environmental problems, putting some of the blame on Scott. She argued the state lately has pursued far fewer enforcement cases.

Florida officials are still assessing the economic impact of the algae on Indian River, Martin and Saint Lucie counties, whose annual economy is roughly $1.96 billion, according to the Treasure Coast Regional Planning Council.

Scientists do not appear to have a consensus about what triggered the bloom. But they generally point to Florida’s extreme heat and nutrient-polluted runoff -- including septic waste and manure from the suburbs and farms surrounding Lake Okeechobee.

Some residents and environmental groups say Scott should set tighter limits on such pollution.

The governor in part blames the federal government, arguing the Army Corps of Engineers is protecting the decades-old Herbert Hoover Dike nearby by releasing lake water.

Florida Department of Environmental Protection spokeswoman Dee Ann Miller said Thursday that test results for the algae show low or undetectable levels of toxins. She said such blooms are most common during the summer and early fall, with high temperatures and abundant sunlight.

"The algal bloom response team takes all algal blooms seriously and all federal, state and local agencies will continue to respond as quickly and efficiently as possible to both observed and reported algal blooms to ensure the health and safety of Floridians, visitors and our natural resources," Miller said.

The long-term solution, say many residents, is to redirect the water to the south. But that is fraught with politics, considering the U.S. Sugar Corp. – which owns land south of the lake – is a major donor to Democratic and Republican politicians, including Scott.

His Let’s Get to Work PAC received $100,000 from the company as recently as June, according to the PAC website. In 2010, U.S. Sugar, the country’s largest sugar manufacturer, struck a deal with the state that included the sale of roughly 27,000 acres of company property. But a local board last year voted down an option to buy more.