Several state agencies are asking the public to take 10 minutes this month to check trees in their communities for signs of invasive insects.
The Washington Invasive Species Council, the Washington State Department of Natural Resources Urban and Community Forestry Program, the Washington State Department of Agriculture and the Washington State University Extension come together each August to ask the public to help them spot invasive wood-boring insects and the damage they cause in trees, a news release by the Washington State Recreation and Conservation Office stated.
“Late summer is often the peak time for these invasive insects to emerge from trees in their adult stage,” the release stated.
In addition to appearing in trees, invasive insects also show up in lights and standing water such as dog bowls and birdbaths, among other locations. Pool filters can also act as traps for invasive insects.
“Researchers and scientists are monitoring for invasive species statewide, but we need the public’s help,” said Stephanie Helms, executive coordinator of the Washington Invasive Species Council, in the release. “Public awareness of emerging invasive pest issues can greatly reduce the risk of spread, as human travel plays a major role in the movement of unwanted insects.”
At least 70 new insect species have been detected in Washington since 1990, according to a state study. The public found 36% of the new insects first, highlighting the importance of an educated and aware public, the release stated.
“While you are outside enjoying the summer, take 10 minutes to search your yards and neighborhood trees,” Zeima Kassahun, of the Washington Department of Natural Resources, said in the release. “If you see or suspect you see an invasive insect, report your findings, including a picture, to the Washington Invasives mobile app or on the Washington Invasive Species Council website, which routes the report to organizations that can help.”
The Washington Invasives mobile app can be downloaded at invasivespecies.wa.gov/report-a-sighting/.
“Alert residents can help spot infestations when they are easy to handle,” Helms said. “All it takes is 10 minutes to check your trees this August, and you could save the state hundreds of thousands, if not millions, in potential invasive species management costs. And yours could be the report that saves your neighborhood’s trees.”
Initial indications of invasive insect damage to trees include sudden dieback or death among trees that are otherwise vigorous and healthy. The release stated that if residents see signs of invasive insect damage, they should investigate further and look for sawdust, exit holes or adult beetles.
Invasive insects of greater concern
• Invasive longhorned beetles: The larvae of this group of large beetles feed on and in the wood of a tree. When the beetles become adults, they emerge through holes that weaken the tree further. These beetles are extremely destructive to hardwood trees. While it is not known to be established in Washington today, it has been found and swiftly stopped multiple times in the past, saving potentially millions of dollars in damages along with countless trees. Invasive longhorn beetles can easily be mistaken for native lookalikes, such as the banded alder borer and spotted pine sawyer, which are beneficial to Washington’s forests.
• Emerald ash borer: This small, wood-boring beetle attacks and kills ash trees. The larvae burrow under the tree’s bark and eat the sapwood. Once damaged, the sapwood can’t transport water and nutrients, causing the tree to die gradually. While not yet known to be in Washington, it was detected outside Portland, Oregon, in 2022 and most recently in Vancouver, British Columbia, in 2024.
• Spotted lanternfly: This piercing, sucking insect feeds on sap from a variety of trees, including apples, cherries, grapes, plums, walnuts and hops. While not yet found in Washington, the lanternfly has been intercepted in California as a hitchhiker on goods coming from the eastern United States where it is established.
How to locate invasive species
• Search trees, outdoor light fixtures, outdoor equipment and standing water for signs of invasive insects.
• Report sightings
• If a suspected invasive insect is found alive, take a photograph and submit a report with details to the Washington Invasive Species Council either through the mobile app or website, invasivespecies.wa.gov/.
Take these steps
If a suspected invasive insect is found dead in lamps, pools, etc., take the following steps:
• Collect and place the insect onto something with a white background (such as a paper plate, piece of paper or paper towel).
• Photograph the insect from multiple angles (top, side, etc.), making sure your photo is in focus.
• Place the insect into a ziplock bag or sealable container for safe storage. Entomologists might ask you to mail the specimen to a lab for identification.
• Report the sighting to the Washington Invasive Species Council mobile app or website.
• Repeat as often as you find a suspicious insect.
For those not interested in getting up close and personal to the insects, the release stated that one can still participate in August Tree Check Month by taking these actions to prevent the spread of unwanted pests:
• Don’t move firewood from distant locations. Buy firewood where you’ll burn it or gather it on site when permitted. If you move firewood, you also might be moving invasive insects hiding in the wood.
• Don’t move a pest. When traveling locally or moving to a new area, check your bags, outdoor gear and boxes to make sure they are insect-free. Invasive insects, which can be in any life stage from egg to adult, can tag along easily in bags, equipment and boxes, as well as on items that have been stored outside or in your garage.
