Working toward citrus mealybug IPM in California citrus systems

Citrus mealybug, Planococcus citri, has been increasingly reported from the San Joaquin Valley since 2019. Limited use of neonicotinoids, loss of chlorpyrifos, and changing weather conditions may be some of the factors leading to mealybug pressure.
Due to a lack of information field ecology of this emerging issue, growers are facing a challenge to manage this pest.
The goal of this Citrus Research Board-funded project was to improve knowledge of pest biology, field ecology, monitoring, and near erm management using insecticides already registered for use in citrus.
We monitored orchards with a history of infestation to explore mealybug movement within the tree canopy, the number of generations, and their occurrence during the fruit growing season.
Results showed that although populations were present throughout the year, movement of mealybug started in the first week of April, suggesting the first generation of the season.
First generation immatures moved into the new leaves growth and fed, second and the successive generations moved to the fruit and multiplied.
Male trap data shows six distinct peaks suggesting five-six complete generations.
Field trials to determine efficacy and timing of registered pesticides showed that some products work better than others, and early season application of insecticides prevents from population build up.
These findings will direct future research evaluating thresholds and how natural enemies and augmentative biocontrol can be incorporated, subsequently helping pest control advisors with pest monitoring and timely management.

XV International Citrus Congress

S. Gautam, J. Wenger

Planococcus citri, management, seasonal phenology, monitoring

https://doi.org/10.17660/ActaHortic.2026.1448.77