Scolytinae in Nursery and Fruit Crops of Western Kentucky and Seasonal Population Patterns of Four Invasive Ambrosia Beetles

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) inoculate species specific symbiotic fungi into the sapwood of their hosts. Some fungi are innocuous, but others are pathogenic and can kill plants in a short time. The main objectives of this study were to identify ambrosia beetle species found in wholesale and retail nurseries and an apple orchard in western Kentucky and monitor population abundance and phenology of the more common invasive ambrosia beetles. Baker traps baited with ultra-high or standard release ethanol were deployed in late February or March and removed in either fall (2016 and 2017) or August (2018). Sixteen ambrosia beetle species were captured, and eight of them were invasive. The invasive species Cnestus mutilatus (Blandford), Xylosandrus crassiusculus (Motschulsky), Xylosandrus germanus (Blandford), and Xyleborinus saxesenii (Ratzeburg) were the most common and abundant species. The highest counts of these invasive species were recorded from April to May. In addition, we are reporting 13 bark beetle species captured in this study; among them, Phloeotribus dentrifrons (Blackman) and Thysanoes fimbricornis LeConte are reported for the first time for Kentucky, whereas Scolytus multistriatus (Marsham) was the only invasive bark beetle collected.