First identified in 2009 in Florida, experts say this invasive species has spread throughout the state since its discovery. The rugose spiraling whitefly will suck the nutrients from a plant or tree, causing wilting, stunting, leaf drop and yellowing, which will cause severe damage.
According to the University of Florida IFAS Extension, this whitefly is capable of infesting a wide range of plants, such as gumbo limbo, banana, black olive, mango, palms, live oak, some shrubs such as cocoplum, wax myrtle and copperleaf and more.
The rugose spiraling whitefly is very closely related to the giant whitefly and they do share similarities in appearance. Adults will be about three times larger than other whiteflies found in the United States, and Arborjet says they are more docile and slower moving.
Adult rugose spiraling whiteflies can typically be found on the undersides of plant leaves to reproduce and feed.
“When insects feed on plants, it puts the plants under stress,” the University of Florida IFAS Extension says online. “Therefore, proper watering and fertilizing is important to keep the tree as healthy as possible. If the palms are in bad shape, it is suggested to apply fertilizer at the recommended label rate. Also, if you prune an infested tree/shrub or if your infested palms lose their fronds, take them to your closest landfill to prevent further spread of this whitefly.”
Arborjet says the predatory wasp has helped keep the rugose spiraling whitefly in check, but as the whitefly has declined in numbers, so has the wasp. Until these numbers have been reestablished, it’s recommended that injection treatments be used, as it won’t harm the environment or bee population.
Symptoms and maintenance
The symptoms that will most notably signal an infestation are the abundance of waxy material covering the leaves, as well as excessive sooty mold. Much like other insects similar to the whitefly, they will produce honeydew. Be on the lookout for white spirals and a build-up of this white, waxy substance on the underside of leaves. This substance will coat the eggs and immature whiteflies.
If you notice the white spirals forming, take immediate action. The University of Florida IFAS Extension recommends thoroughly washing smaller plants off with a strong stream of water. They recommend following this up with insecticidal soap or horticultural oil sprayed once a week for about three to four weeks. If needed, the process can be repeated.
According to the University of Florida IFAS Extension, one of the best options for maintenance is taking preventative measures before an infestation occurs.
“The spiraling eggs are easy to see and are a good target to look for,” the University of Florida IFAS Extension says online. “It is easier and cheaper to treat when the infestation first starts. Do not wait until you see the leaves covered in white floccules of wax, honeydew or sooty mold.”
They also recommend keeping an eye on natural enemies of the rugose spiraling whitefly and taking advantage of their presence in the landscape. A few natural enemies can include ladybugs and parasitic wasps, and the University of Florida IFAS Extension says these enemies will prove very beneficial when it comes to long-term management of the rugose spiraling whitefly.
Along those same lines, the extension recommends avoiding any insecticides that might kill these natural enemies instead of the whitefly.
For larger plants and heavily infested ornamental trees, the University of Florida IFAS Extension again recommends thoroughly washing plants off with a strong stream of water. They also recommend using a systemic insecticide specifically labeled for whitefly control in landscapes that can be applied to the soil as a drench, granule or tablet.
The University of Florida IFAS Extension says systemics may take several weeks to be effective for larger trees but they will last for about nine to 12 months.
“Systemic insecticides can provide longer term control than contact insecticides, particularly if the systemic insecticide is applied to the soil or trunk,” the University of Florida IFAS Extension says online. “It is recommended that where possible it is preferable to use systemic products.”