A new avocado pest (Lepidoptera: Gracillariidae: Caloptilia) on the move: Genetic confirmation and parasitoid associations across southern California

Since its initial detection in San Diego County in 2020, a species of Caloptilia moth (Lepidoptera: Gracillariidae) has become a persistent pest in California's avocado-growing regions. By 2025, infestations have been documented in Santa Barbara, Ventura, Orange, Riverside, and San Diego counties. The larvae exhibit a hypermetamorphic life cycle, transitioning from leaf-mining to leaf-rolling behaviors, forming distinctive cone-shaped leaf rolls that serve as both feeding and pupation sites. This feeding activity leads to defoliation, increasing the risk of sunburn on fruit and posing significant threats, particularly to young avocado trees. To determine the pest's identity and distribution, we conducted extensive field sampling across the five counties. Mitochondrial cytochrome oxidase I barcode sequencing confirmed that the specimens collected from all locations belong to the same Caloptilia species. Laboratory rearing of field-collected samples yielded several parasitoid species within the superfamily Chalcidoidea, providing valuable natural enemies for identification and highlighting potential avenues for biological control. This foundational research is the first step in developing a comprehensive Integrated Pest Management program for this Caloptilia moth species. By confirming the pest's identity and uncovering its natural enemies, we lay the groundwork for future studies aimed at understanding its biology, assessing the efficacy of biological control agents, and implementing sustainable management strategies to mitigate its impact on California's avocado industry.