Seasonal phenology of Carpophilus truncatus (Coleoptera: Nitidulidae) in almond orchards in California

The recently introduced Carpophilus truncatus (Coleoptera: Nitidulidae) beetle poses a potential threat to California's almond industry. This study investigates the seasonal phenology of C. truncatus in California almond orchards to understand its activity patterns and develop effective management strategies in future. We are monitoring the beetle populations in several highly infested almond orchards in the central valley beginning from December 2023, and monitoring will be continued until the end of the season. Techniques include deploying emergence cages with mummy nuts at various locations within the orchards and collecting samples (mummy nuts and harvest samples) at regular intervals. The emergence cages will be inspected on weekly basis for any kind of beetle activity. The collected samples will be assessed in the laboratory for different stages of Carpophilus beetles. Additionally, we continue to examine infested almond nuts under the stereoscope to determine the developmental stages of the beetle (eggs, larvae, pupae and adults) within. By correlating trap captures and developmental stages with weather data, we aimed to identify peak activity periods and potential environmental factors influencing C. truncatus populations.

This study provides the first comprehensive data on the seasonal phenology of C. truncatus in California almonds. Understanding its activity patterns will be crucial for developing targeted pest management strategies, such as optimizing insecticide application timing or implementing cultural controls.