Vespa mandarinia Smith 1852 is a semi-specialized predator of other social Hymenoptera and one of the two largest species of Vespa. Several individuals of this predatory wasp were detected in Canada and the United States in 2019, including an entire nest that was located and destroyed on Vancouver Island, British Columbia. The Washington State Department of Agriculture and the United States Department of Agriculture’s Animal and Plant Health Inspection Service have collaborated to survey Washington State for V. mandarinia since 2020, using traps staffed by agency personnel, collaborators from local governments and nongovernmental organizations, and the general public. Trap data and public reports were used to select sites for live-trapping or net surveys, and live hornets captured in these efforts were subsequently collected and fitted with radio tags to locate nests. The survey ultimately led to the discovery of a V. mandarinia nest in October 2020, and three nests in August and September 2021. All of the nests were located within in red alder trees (Alnus rubra), with one just above the ground in a standing dead tree, and the other three in cavities ~2 to 5 meters above the ground in living trees. The number of combs in each nest varied between four and ten, cells between 418 and 1,329, and total hornets per nest between 449 and 1,474 (including immature and mature stages). Together, the four nests indicate an incipient population of V. mandarinia in the Cascadia region, and ongoing action by local, state, provincial, and federal governments, and residents of both countries is required to avoid the establishment of this exotic species in the region.

The Japanese beetle, Popillia japonica (Newman, 1841) (Coleoptera: Scarabaeidae), was first detected in southern Washington State in 2020. Widespread trapping efforts ensued, and over 23,000 individuals were collected in both 2021 and 2022 in this region known for specialty crop production. The invasion of Japanese beetle is of major concern as it feeds on over 300 plant species and has shown an ability to spread across landscapes. Here, we created a habitat suitability model for Japanese beetle in Washington and used dispersal models to forecast invasion scenarios. Our models predict that the area of current establishment occurs in a region with highly suitable habitat. Moreover, vast areas of habitat that are likely highly suitable for Japanese beetle occur in coastal areas of western Washington, with medium to highly suitable habitat in central and eastern Washington. Dispersal models suggested that the beetle could spread throughout Washington within 20 years without management, which justifies quarantine and eradication measures. Timely map-based predictions can be useful tools to guide management of invasive species while also increasing citizen engagement to invaders.