D3092: Citrus mealybug, Planococcus citri Risso, seasonal phenology in the San Joaquin Valley

Citrus mealybug, Planococcus citri Risso, is a generalist pest known to damage commercial citrus in Southern California. In the San Joaquin Valley, citrus mealybug has been a minor pest held in check by local climactic, cultural, and biological conditions. Beginning in 2019 San Joaquin Valley citrus mealybug populations grew to economically damaging levels, resulting in losses for lemon and navel growers. Despite its longtime presence in the San Joaquin Valley, little is known about the citrus mealybug’s basic phenology and seasonal cycle in the region. In 2022 and 2023, a field study was conducted to understand the movement of citrus mealybug within the tree canopy in a mature citrus orchard. The aims of the study are to understand how citrus mealybug develops, understand generations, and monitor movement within the trees. Thirteen trees with history of infestation were monitored in February of 2022 and 105 trees in May 2023. Double sided sticky tape was used to track movement in the tree. As well as traps to monitor male flights. These were replaced once a week. Initial data from 2022 at least seven generations with overwintering populations moving into the tree canopy from March to June. During fruit set in June mealybug move to the fruit and stay there until harvest. Results are discussed in the context of generations in the SJV. Research supported in part by CRB 5500-501 and industry gifts of pesticides and funding.