Lebbeck mealybugs were first discovered in Florida in citrus trees in Highlands County in 2019, and they have since been found in commercial groves in 11 different counties and in residential citrus in two counties. These insects feed on fruit, leaves and stems, and the damage they do ranges from ruining fruit for the fresh fruit market and causing tree damage to stunting the growth of young trees, creating a buildup of sooty mold, and even killing young trees; they may even contribute to fruit drop.
UF/IFAS’s Lauren Diepenbrock gave a presentation on the lebbeck mealybug and the importance of incorporating lebbeck mealybug management into current management programs at the 2021 Florida Citrus Growers’ Institute.
Challenges in Combating Lebbeck Mealybugs
There are a handful of challenges Florida citrus growers face in managing lebbeck mealybugs. For one, the instars of the various stages of the insects’ life cycle are tiny and blend in with the bark of citrus trees, making them hard to spot. Unfortunately, lebbeck mealybugs are not usually detected until the damage they cause becomes apparent because of this. Another challenge is that many of the insects’ stages don’t feed, meaning systemic control materials will not reach all stages.
Additional challenges include other insects. First, as an invasive species, there are only a handful of predatory insects that target lebbeck mealybugs, but research in other areas of the world has shown that using predatory insects is an important factor in mealybug control. Furthermore, research has shown that ants in the grove—mostly imported fire ants—will “fam” lebbeck mealybugs for the mealybugs’ honeydew and protect the mealybugs from predators.
Lastly, lebbeck mealybugs are easily dispersed by the wind, tools, and even workers, and they are not barred from reaching young citrus trees by Individual Protective Covers like Asian citrus psyllids.
Recommendations for Lebbeck Mealybug Management
Research is ongoing according to Diepenbrock into the best practices for managing lebbeck mealybugs, such as the best times to manage infestations, the best combinations of adjuvants and insecticides, and more. Diepenbrock shared the following current recommendations:
- Combine lebbeck mealybugs management with management for other pest programs you’re currently doing. Control materials that target Asian citrus psyllids during flush also impact mealybugs.
- Target control applications to the trees’ phenology and the mealybugs’ life cycles.
- Look into taking advantage of predatory insects like the ladybeetle known as the mealybug destroyer, predatory flies and caterpillars, and lacewing larvae. Consider using systemic and materials with “softer” chemistries to preserve predatory insect populations.
- Control imported fire ant populations.
- Minimize the transfer of mealybugs by sanitizing tools and machinery and working in clean parts of the grove before working in infected parts of the grove.
- Stay up-to-date with research-based recommendations for mealybug management.