Careful testing, strict containment and a coordinated, unified response are necessary if we’re going to fight off a looming public health threat — to trees.
The challenge of getting Washington property owners to inspect their yard trees for dangers that are still rare here seems similar to getting healthy people to take precautions against an invisible virus that’s easy to ignore. But that’s what the Washington Department of Natural Resources and the Washington Invasive Species Council are urging everyone to do: spend 10 minutes this month checking your trees for invasive, wood-boring pests before they can do serious damage to your individual landscape and start spreading across the state.
“Your neighbor’s problem will become your problem, over time,” said Justin Bush, executive director of the Invasive Species Council based in Tumwater. “It could take you just 10 minutes to protect your neighbor and protect the whole community.”
That’s only fair, because people and commerce, not natural processes, are the culprits when it comes to the spread of invasive species, Bush said.
“Humans are the problem and they’re responsible for solving the problem as well,” he said. “Invasives don’t move to new areas on their own. They’re always associated with human activities.”
Moving goods from place to place — overland and overseas — is the human activity officials are most worried about. Ports in particular are high-risk locations, Bush said, and there are several in Clark County. State and federal officials do a good job keeping after invasives at ports, but some do slip through, he said.
“Invasives can slip into cargo containers. The eggs can mix with seeds. We’ve seen egg masses on the sides of ships,” he said.
Even your own car or truck can be part of the problem, which is why reminders are sometimes posted along freeways.
“Domestically, we’re urging people not to transport firewood,” Bush said. “Burn it where you bought it. Firewood could be transporting insects. Anything that can move can move invasive species.”
What’s so scary about an invasive species? By definition, an invasive is a newcomer to the landscape, without anything to keep it in check like predators or diseases. An invasive can damage the environment, the economy and even human health.
“Invasive insects impact our healthy forests and, in turn, destroy timber we manage that provides funding for schools, local services and our counties. The damage also increases fire risk and restricts recreation opportunities,” said Commissioner of Public Lands Hilary Franz. “Trees play an important role in our state economy and provide significant environmental benefits from clean air to habitat for wildlife and healthy waterways that support salmon and other fish.”
The best case scenario is stopping all that before it ever starts, Bush said.
“It’s similar to the coronavirus response,” he said. “If we’re successful in what we do, if we can stop the spread quickly, no one will ever see the evidence.”
Four bad bugs
This month is the best time to inspect your trees for four types of bugs you’d rather not see at all, according to the state. Here’s the non-fab four you’re urged to look for:
Asian longhorned beetle: The larvae of this large beetle feeds on hardwood trees. When grown to adulthood, beetles emerge through holes that weaken the tree further. The Asian longhorned beetle isn’t known to be in Washington today, but it has been found here in the past in nurseries and warehouses. A swift response stopped the spread, according to the state.
The beetle is large and robust, and a glossy black with irregular splotches of white on the wings. The antennae have bands of black and gray. Slate-blue pubescence (hairs) grow on the beetles feet and legs.
Emerald ash borer: This small wood-boring beetle attacks and kills ash trees. Larvae burrow under the tree’s bark and eat the sapwood. Once damaged, the sapwood can’t transport water and nutrients, causing the leaves and tree to die gradually. The emerald ash borer is currently spreading westward across the United States, but isn’t known to have reached Washington yet.
“It’s well established on the East Coast. All it would take is one person from there taking one summer vacation out here to transport it,” Bush said. “Sadly, that’s all too common.”
Adult emerald ash borers are a jewel-like metallic green, with an elongated narrow shape about one-half inch long. The insects leave D-shaped exit holes in trees where they’ve grown to adulthood and emerged. Woodpeckers eat ash borer larvae, so heavy woodpecker damage on ash trees is a possible sign of infestation.
Spotted lanternfly: This piercing insect sucks sap from a variety of trees including apple, cherry, plum and walnut, as well as grape vines and hops, a main ingredient in beer. This insect has not been found in Washington, but has been intercepted in California “hitchhiking” on goods coming from the eastern United States, where it is established. The spotted lanternfly likes tree of heaven, which is also an aggressive, invasive species despite the nice name. Avoid planting trees of heaven and remove them from your property.
The spotted lanternfly is about 1-inch long, with distinct black spots on its light brown or gray wings and a distinct red-and-black pattern on its hind wings. Nymphs are black with bright white spots that turn red with age. Egg masses look like a smear of light-colored clay and can be found on plants, outdoor furniture and cars. Adults produce large quantities of honeydew, which can leave soot-like mold at the base of trees.
Asian giant hornet: You might already have seen news coverage of this little monster. Found only in Whatcom County so far, this hornet kills honey bees and has been known to attack anything that threatens its colony, which is usually found on the ground. It can sting multiple times and has powerful venom that can inflict serious injury, or in some cases, death. The Asian giant hornet is 2-inches long with orange and black stripes.
“We don’t know how big a problem it is,” Bush said. “We just know it got to the U.S. and Canada somehow.”
Vancouver urban forester Charles Ray said his department routinely checks for these new invaders when out in the field.
“The only way we are going to know if the pests are here is if the public is aware and knows how to identify them,” he said. “We routinely get calls about pests and check to see if they are one of the invasives.”
On the East Coast, Bush said, people started finding a strange little bug in their swimming pool filters that turned out to be the longhorned beetle years before that invasive was detected by the proper officials.
“That’s a great example of the important role that the public plays,” he said. “You’re familiar with your property. If there’s something weird and new, you’ll be the first to find it. If you see something, say something.”
Diversity is a good way to combat tree pests and diseases and is a goal of Vancouver’s Urban Forestry program, Ray added.
“When a neighborhood starts to plant a mix of trees, breaking up the monotony, it is also a safety check to control any outbreak,” he said in an email. “We want to increase tree diversity; utilize native trees; and utilize insect/disease resistant trees. By increasing diversity, we can reduce the spread of insects and diseases.”
Report, don’t kill
“We’re asking people to take 10 minutes to search the trees in their yards and neighborhoods,” Bush said. “If you find a suspected invasive insect, take a picture and send us information on the Washington Invasives mobile app or on our web site. It’s quick and easy and we’ll connect you with organizations that can help.”
Your photographs of the insect should show enough detail for experts to get a good look. Include an object, such as a coin or pencil, next to the insect to indicate the insect’s size.
Some non-invasive species resemble invasives but don’t cause problems. Report your suspicions but don’t kill the suspected invader, Bush said.