The Rugose Spiraling Whitely (Aleurodicus rugioperculatus), or RSW, made its debut in the U.S. in 2009, wreaking havoc on Gumbo Limbo trees in Miami-Dade County. After its arrival, this invasive pest, thought to originate in Central America, quickly increased its appetite to include over 100 other ornamental plant species, most notably: coconut palms, Christmas palms, and white bird of paradise. The pest rarely kills mature, healthy trees; however, heavy infestations can be detrimental to smaller or unhealthy plants.

Signs of RSW
The most obvious sign of infestation is a buildup of a white, waxy, material covering leaves and fronds. This substance serves as a protective mechanism for eggs and nymphs. A closer look will reveal the namesake characteristic, circular “spiraling” egg patterns on lower sides of leaves.

Damage and Nuisance
“Adult whiteflies congregate on the undersides of leaves to feed and reproduce”, says Dr. Catherine Mannion from UF in her August 2010 publication, Rugose Spiraling Whitefly.

Like other whiteflies, the insects siphon plant sap, which is excreted as “honeydew” after their bodies absorb the nutrients they need. This sugary, sticky substance attracts ants and encourages the growth of black, sooty mold on understory plants and on anything else underneath infested tree leaves. If enough feeding occurs, plants will be unthrifty and/or lose leaves.

Remembering a trip to the Village of Key Biscayne with a colleague Arborist to collaborate with UF and the City’s pest control on treatment strategies, Dr. Stephanie Parker (formerly, Mainscape’s Regional Director of Agronomy) recalled, “It was incredibly messy. Honeydew was getting all over peoples’ cars, homes, and patio furniture. To make matters worse, tiny hair-like waxy filaments were flying in the wind, landing everywhere. Residents were pushing to have all the Gumbo Limbo trees removed. Fortunately, effective treatments were put in place, and this didn’t happen.”

Management of Rugose Spiraling Whitefly
Biological control is a key element in management of RSW. According to Florida Department of Agriculture & Consumer Services, RSW populations declined within a couple years after arriving due to increased numbers of both a parasitic wasp and predatory beetles feeding on them in nature.

The population dynamic between natural predators and the pests they feed upon typically ebbs and flows. We have seen a recent resurgence of RSW most commonly on coconut palms. Though not nearly as severe an infestation as the initial one, it is heavy enough in some locations to warrant treatment. Trunk injection with a systemic product provides excellent control, lasting up to a year.

Mainscape personnel will be on the lookout for RSW on each property we maintain and will provide proposals for treatment of palms and trees, as needed. If a RSW infestation is suspected, please contact Customer Service at 1-800-481-0096 or www.mainscape.com.