Climate change is bringing new insect pests into our gardens.
A change in climate means that areas that were once inhospitable to insects are now favorable habitat. As the climate shifts, new invasive insects will find their way into our gardens to wreak damage and introduce new diseases.
Climate change isn’t the only way invasive insects get into new areas. They hitchhike on products, ships, planes, trucks and even luggage that comes into the country. Insects and their eggs are small and can hide in the tiniest of spaces. If upon landing they find a hospitable climate and a mate, they can begin spreading.
Remember the murder hornet of a few years back? More properly called the northern giant hornet, this insect first appeared on Vancouver Island, British Columbia, in August 2019 and then in northern Whatcom County later that year. The hornet attacks honey bee hives and can destroy a colony in a matter of hours. Honey bees are important to our agriculture system.
Once the hornet had been observed, the Washington State Department of Agriculture and other federal and Canadian agencies launched an extensive search to eradicate nest sites. Hornets were discovered and eradicated in 2020 and 2021 with significant help from the public. Tracking continued from 2022 to late 2024, but no more wasps were found. Earlier this month, the hornet was declared eradicated. A success story yes, but the next invasive insect is on the horizon.
Japanese beetles have been found in the Yakima Valley and near the Tri-Cities. The WSDA has had a scouting program for Japanese beetles for many years without issue. Japanese beetles are established in the eastern U.S. and are a highly invasive pest of more than 300 plants, including turf, roses, grapes, hops and dozens of other plants. If they were to establish themselves here, they would have a significant impact on residential and public gardens, lawns, vineyards, orchards and field crops.
Beyond the damage they cause, they make it difficult to move agricultural crops and nursery stock to markets around the country and overseas. Gardeners and farmers would experience increasing and recurring lawn and crop damage, increasing pest control costs and a general increase in pesticide use.
In 2020, WSDA trapped two Japanese beetles in Grandview and one in Sunnyside. In 2021 and 2022, it trapped 24,000 and 23,000, respectively, in the same areas.
As a result, the WSDA is conducting a major eradication program in the area that involves trapping, grub treatment on lawns and quarantines on the movements of plants, soil and garden debris. This spring, home owners will be asked to voluntarily sign up to get their lawns treated to kill the beetle larvae and break the insect’s life cycle.
To allay any fears for us in Spokane, the Japanese beetle has not been found here, but each of us needs to learn what they look like and report any suspicious bugs to the WSDA through the department’s website: agr.wa.gov/departments/insects-pests-and-weeds/insects/japanese-beetle/report-japanese-beetle
