D3113: A new avocado pest (Lepidoptera: Gracillariidae: Caloptilia) on the move: Genetic confirmation and parasitoid associations across southern California

A new insect pest of avocados was reported in San Diego County in 2020 and identified as a moth in the genus Caloptilia (Lepidoptera: Gracillariidae). Little was known about this insect, including its origin, distribution, natural enemies, and management options. Since its discovery, it has become a persistent pest across California’s avocado-growing regions, with infestations now documented in San Luis Obispo, Santa Barbara, Ventura, Orange, Riverside, and San Diego counties. Growers report that feeding damage causes defoliation, increases fruit sunburn risk, and severely affects young avocado trees. To establish baseline knowledge for Integrated Pest Management (IPM) development, we conducted field sampling across six counties and recorded life-history observations. Larvae exhibit a hypermetamorphic life cycle, beginning as leaf miners and transitioning into leaf rollers that create distinctive cone-shaped rolls used for feeding and pupation. Laboratory rearing of parasitized field samples revealed two parasitoid species in the family Eulophidae (Sympiesis sp. and Elachertus sp.), suggesting existing resident biological control with parasitism rates up to 45.2%. A subset of samples is being processed for mitochondrial cytochrome oxidase I (COI) barcoding to confirm species identity. A survey of 101 avocado varieties in the Avocado Variety Collection indicated universal susceptibility, with infestation levels ranging from 28.3% to 90.5% (mean 56.8%, n = 4 trees per variety). By documenting pest identity, distribution, and natural enemies, this research provides essential insights into the ‘avocado cone roller’s’ ecology and potential impact on California’s evolving avocado industry.