Flight phenology and influence of region and habitat on the abundance of Xylosandrus germanus and Anisandrus maiche (Coleoptera: Curculionidae: Scolytinae) in New York.

Abstract

The non-native wood-boring and symbiotic fungus-culturing Xylosandrus germanus (Blandford) was first reported in New York apple orchards in 2013. Trapping surveys have been conducted annually since to assist growers in timely applications of preventative control measures. In 2021, a similar-looking introduced species, Anisandrus maiche (Kurentsov), was identified in traps in west central New York. Anisandrus maiche was first recorded in 2005 in Pennsylvania but its history in New York was unclear due to potential misidentification. We collected and identified ambrosia beetles using ethanol-baited bottle traps in 2022 and 2023 in New York at 2 commercial apple orchards near Lake Ontario and 2 cider apple orchards in the lower Finger Lakes district. Traps were placed in a forest interior, the forest edge, and the orchard edge at each site. Xylosandrus germanus was trapped from mid-April into early October; it was abundant in the Lake Ontario region but less so in the Finger Lakes. In contrast, counts of A. maiche were very high in the Finger Lakes but extremely low near Lake Ontario. It was trapped from late-May to mid-September. Most other bark and ambrosia beetle species were uncommon. Captures of X. germanus and A. maiche were generally highest in the forest interior and declined toward the orchard edge, but each species was usually present in traps across habitats at the same time. Thus, the practice of trapping at forest edges should continue. Both species can potentially infest stressed trees, including in orchards, throughout the growing season.