University of Florida Institute of Food and Agricultural Sciences entomologist Lauren Diepenbrock provided an update on lebbeck mealybug during the 2021 Florida Citrus Growers’ Institute. The pest, first found in Florida commercial citrus in 2019, feeds on and damages citrus, causing up to 70% fruit drop in heavily infested groves.
According to Diepenbrock, damaged fruit will not be marketable for the fresh market. She says the quality of juice is okay as long as the fruit makes it to harvest.
Florida’s subtropical climate is well suited for lebbeck mealybug. It thrives in high humidity and subsists on hosts other than citrus, including fruit, vegetable and field crops as well as ornamentals.
SANITATION IS KEY
Lebbeck mealybugs typically settle at branch junctions, underneath calyx buttons and on the blossom end of fruit. Small in size, the pest is easily transported by humans, farm equipment, tools and animals. Learn how to identify the lebbeck mealybug here.
Diepenbrock says it is important to sanitize all tools and equipment to prevent spread. For small tools, thorough cleaning with dish soap and bleach is recommended. Steam is another effective sanitation method. Small equipment and tools should be steamed at 120 degrees for at least 10 to 15 minutes.
For contact sanitization, researchers tested isopropyl alcohol. Diepenbrock says two sprays of 70% or 90% resulted in almost 100% mortality of the crawler.
Research is still being done to determine the best method to sanitize large equipment. In the meantime, growers should be cleaning their equipment used in fields with infestation. If possible, Diepenbrock recommends working in infested fields after visiting clean fields.
Chemical controls for lebbeck mealybug are also under investigation. Diepenbrock reports carbamates, organophosphates and butenolides have shown high efficacy. She says most available adjuvants provide some knockdown alone and should increase efficacy of insecticides.
Individual protective covers (IPCs) have gained attraction as a new growing environment that excludes Asian citrus psyllids and protects young trees from citrus greening. However, Diepenbrock warns that the downfall is IPCs create a great environment for tiny pests to establish, like the lebbeck mealybug. So far, BotaniGard ES, Botanigard MAXX and Centaur seem likely to work for controlling the pest in IPC environments, she says.
To fit lebbeck mealybug management into preestablished pest management programs, Diepenbrock says to choose materials that work on both the mealybug and other pests of concern. She also recommends targeting applications to tree phenology and pest activity periods and using systemic, softer chemistries to preserve predatory insects.