Whitefly situation improving

Since 2009 when the first report of a whitefly surfaced in Miami-Dade County, the epidemic has spread across the islands of Monroe County and left residents and homeowners scratching the heads for a solution.

Tuesday evening, during the Marathon City Council meeting, county extension agent Kim Gabel presented the council with some positive news.

“We’ve been talking whitefly for over a year now,” Gabel told the council following a workshop with 10 area Master Gardeners. “I conducted some education with them to help look for the Rugose spiraling whitefly, to help them determine when they’re alive or dead. Sometimes, we’re fooled into thinking we have the insects when in fact they might be gone.”

Beetles and wasps that already existed in South Florida, Gabel said, are natural predators for the Gumbo Limbo Spiraling whitefly that is believed to originate in Central America.

“It’s all a numbers game,” she continued. “Last year, they weren’t here [in the Keys] in large numbers, but once they find their food source here, they’re able to exploit that food source.”

The first step in treating foliage under siege by white, waxy mold is to wash plants with horticultural oils and insecticidal soaps. The Extension Agency advised several applications 7-10 days apart to help control the pests, but large infestations may require further topical insecticide applications or use of systemics that are applied directly to the infested plant or soil.

The use of chemicals can jeopardize the populations of beneficial beetles and wasps, Gabel cautioned. She told the council the Crane Point Subdivision as well as several neighborhoods between 23rd and 109th Streets in Marathon are holding larger populations of beetles and wasps that will ultimately be the best line of defense against the whiteflies.

“There’ve been cases where people apply the products and are not seeing results, and they don’t wait the recommended time between treatments,” she said. “When done too quickly, it can harm the plant by killing off new growth. Also, the use of the same products over and over again has the potential for a whitefly to develop a resistance to treatment.”

Councilman Rich Keating asked how the warmer, rainy months on the horizon will affect the populations, but Gabel painted a picture of little relief with increasing temperatures.

When the thermometer hangs around 65 degrees, it takes about 40-45 days for a Rugose Spiraling whitefly to fully develop from an egg into an adult.

“When temperature average 86 degrees, it takes about 20-25 days,” she reported. “Therefore, their life cycle shortens. Only through monitoring on a consistent basis will be we able to determine whether or not it’s becoming a problem again.”

In addition to hosting a homeowners workshop on Monday, April 9 from 3-4:30 pm at the Marathon Government Center. Gabel will have different samples on hand to help homeowners properly identify the stage of their whitefly problem.

On May 18 from 10 am to 12 noon, Dr. Catharine Mannion, will host a discussion for landscapers and pest control operators to provide as much industry knowledge as is currently available.

Those having their property treated, Gabel added, need to ask important questions regarding what pesticides companies are using, specifically how their plants will be treated and whether or not a service provider has the proper insurance.

“Be sure to ask someone for several referrals from past clients,” she advised.

For more information about treating whiteflies on your property or to learn how to submit infested plant samples directly to Gabel’s office through the county’s courier service, visit http://monroe.ifas.ufl.edu or call (305) 292-4501.