An update on lebbeck mealybug, a relatively new pest of Florida citrus, was provided recently by University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) entomologist Lauren Diepenbrock. Diepenbrock, who works at the Citrus Research and Education Center, prepared the presentation for the April Florida Citrus Growers Institute, which was canceled due to COVID-19.
Lebbeck mealybug was found in Florida citrus in June 2019. It has now been detected in commercial citrus groves in Brevard, Charlotte, DeSoto, Hardee, Hendry, Highlands, Indian River, Lee, Miami Dade and Polk counties. Learn how to identify the lebbeck mealybug here.
The non-native lebbeck mealybug is a serious citrus pest around the world. It causes fruit distortion, making fresh fruit unmarketable. Other damage caused by the pest includes fruit drop, leaf chlorosis, branch dieback and death of young trees. Diepenbrock indicated fruit going into juice may or may not be severely impacted, depending on fruit quality and the amount of fruit drop.
Lebbeck mealybug has many host plants, including fruit trees and ornamental plants in Florida. It has been confused with cottony cushion scale and woolly whitefly, according to Diepenbrock.
Diepenbrock reported that chemical classes showing high efficacy against the pest, based on lab data, include organophosphates, neonics, butenolides and fenpyroximate. She added that 435 oil can enhance efficacy. Pyrethroids are the least effective chemicals for control. In field application of chemicals, “coverage is key,” Diepenbrock said.
Her presentation also includes information about biological control. “Biological controls are key to managing lebbeck mealybug in other citrus-producing regions,” Diepenbrock said.
She addressed biological control options when working to manage HLB-spreading Asian citrus psyllids (ACP). “ACP sprays can reduce predators locally,” and growers “may need to supplement and/or provide alternate habitat to maintain populations nearby,” she said. Other tips for working with Lebbeck mealybug and ACP in the same groves include using materials with less toxicity to beneficials and timing insecticide applications to pest activity.
Lebbeck mealybugs can walk to new locations at the rate of approximately half-an-inch per minute, and may possibly be spread by wind. Diepenbrock indicated they can also be spread by plant debris and on equipment being moved between groves. Steam sanitizing reduces spread on equipment. She suggested that growers working in different groves should work in infested groves last.
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