By Lukasz Stelinski
As summer takes hold in June, Asian citrus psyllid (ACP) populations are often high coinciding with availability of new flush. This is also a time when natural enemies can provide meaningful ACP suppression. Growers can improve biological control by making management decisions that help predators and parasitoids survive and function in the grove.
MANAGE ANTS
One important step is to manage ants. Ants feed on honeydew produced by ACP nymphs and may protect nymphs from natural enemies. Recent research in Florida showed that trees with ants had more ACP and fewer important predators, including lady beetles and spiders. Fire ants were especially disruptive because they attacked lady beetle larvae and prevented them from feeding on ACP nymphs. Where practical, use ant baits or trunk barriers to reduce ant movement into tree canopies, especially during periods of active flush.
LIMIT SPRAYS
A second step is to conserve beneficial insects by avoiding unnecessary broad-spectrum insecticide applications during summer. Lady beetles, lacewings, syrphid flies, spiders and Tamarixia wasps can all contribute to ACP suppression, but they are vulnerable to disruptive sprays. When treatment is needed, choose more selective materials and time applications carefully to reduce impacts on beneficials.
ENHANCE ENVIRONMENT
Finally, maintain a grove environment that supports natural enemies. Groundcover or flowering plants near blocks can provide nectar, pollen and shelter for adult predators and parasitoids. These resources can help keep beneficial insects in the grove longer and improve their ability to respond when ACP nymphs appear on flush
INTEGRATE STRATEGIES
Biological control will not replace ACP management, but during summer it can help reduce pest pressure and improve the performance of an integrated program. The key is to remove barriers to natural enemy activity, especially ants, and avoid practices that unnecessarily disrupt beneficial insects.
Lukasz Stelinski is a professor at the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center in Lake Alfred.
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