Home & Garden

On the hunt for pests, diseases in Vizcaya’s gardens

David Hardy, a historic landscape specialist for Vizcaya gardens, shows off the damage mealy worms can wreak on plants.
David Hardy, a historic landscape specialist for Vizcaya gardens, shows off the damage mealy worms can wreak on plants. Miami Herald

David Hardy calls them Toxic Tuesdays.

That’s when he drives around Vizcaya’s gardens in his golf cart, stopping to inspect the thousands of plants on the property for diseases and pests.

Hardy, a historic landscape specialist for Vizcaya, hunts for signs of pests like sooty mold, a black substance covering a plant’s leaves and bark that is caused by sap-sucking insects.

Hunting for pests and disease is part of the job when you help run gardens like Vizcaya, and Hardy, along with a Vizcaya colleague, just returned from a series of lectures and seminars in Washington that were designed to help them improve their identification and prevention skills.

Vizcaya is now a member of the Sentinel Plant Network, joining Montgomery Botanic Center and Pinecrest Gardens in the Miami ranks of the nearly 500-member system.

Network sentinels have a “boots on the ground” mentality for rooting out pests and disease, said network manager Daniel Stern. The nearly 10,000 public garden professionals collect data like leaves, bugs and symptoms of disease and send them to national headquarters for analysis.

Next could be a quarantine of the area (similar to an Oriental fruit fly issue in Redlands), or topical solutions if officials deem the problem significant enough.

Hardy favors natural solutions like fighting diseases with soap or releasing hundreds of ladybugs to eat aphids and mealyworms.

Vizcaya also works with diagnostic facilities from the University of Florida, including using the school’s traps to help hunt for pests.

Around 50,000 invasive species are in the country right now, and Hardy says new ones are coming all the time — particularly through ports and airports.

“Miami is a particularly vulnerable spot through which diseases and pests come through,” he said. “We are, in many ways, the first line of defense.”

These invasive pests can be benign, but more often than not they run amok without any natural predators.

Significant damage is done every year by invasive pests and diseases. Hardy said estimates range from $50 to $100 billion every year in the United States for everything from cash crops like citrus to ornamentals.

The best example of this is citrus greening, which is wreaking havoc on Florida’s citrus industry. In this case, Vizcaya isn’t alone in its research.

“Those are industries that have a very keen eye on these issues,” Hardy said.

That’s what makes networks like this important, Stern said.

“What we know about invasive species biology we’ve learned the hard way,” he said. “The longer a species goes undetected, the more area it infects and the more expensive and difficult it is to eradicate it.”

Hardy said other than citrus greening, he’s focused on the rugose whitefly, while keeping an eye out for the arrival of sudden oak death, something horticulturalists through the South fear may happen soon.

Stern said the network’s partnership with the USDA national institute of food and agriculture and the National Invasive Species Council has led to proactive action throughout the country.

One network member, the Chicago botanic garden, recently became one of the first places in Illinois to discover the viburnum beetle, as well as publish an article about their discovery of an invasive earthworm, the Asian jumping worm.

Having a breadth of information quickly “sets the stage for regulatory officials to have a rapid and thoughtful response, and that's key to eradication,” he said.

Back in Miami, Hardy said Vizcaya is moving toward hosting community classes for gardeners and children that will train them to spot pests and diseases so they can be their own sentinels.

Hardy said he hopes these classes, like his training, help prepare Floridians to better handle what is thrown at them.

“We’re all keeping an eye out for the next big new thing,” he said.