How Government-Released Beetles Invaded a Portland, Oregon Neighborhood
The Galerucella leaf beetle. PhotoJanski / Shutterstock.com
No, it's not the plot of the next Syfy original movie.
A beetle species, released as part of a government program aimed at destroying an invasive weed in an Oregon wildlife refuge, has swarmed into a neighborhood in southeast Portland and is now chowing down on crepe myrtle trees, roses and other plants.
The leaf beetles do not bite and are not harmful to people, pets or wildlife, according to information provided by the Oregon Department of Agriculture’s noxious weed control program on Wednesday. And, for now at least, the insects seem to be confined to one neighborhood, Sellwood-Moreland.
Officials at the Department of Agriculture have attributed the beetle migration to unusual weather and other environmental factors, and they expect that the insects will move on in a few days.
In the meantime, the beetles are making their presence known to the locals.
“They’re just all over the neighborhood and they’re destroying lots of people’s shrubs and trees,” said Barbara Bernstein, a local environmental journalist who lives in Sellwood-Moreland. "I can’t walk out of my house without getting assaulted by all these beetles. It’s horrible. It’s like a biblical plague."
Bernstein first began to notice the insects last weekend. She was not alone.
“They are in gardens, eating plants. In mine, they seem to like zucchini, green beans, and my grapes,” resident Karen Barnack wrote in an Aug. 9 comment on Portland’s Bureau of Environmental Services website.
Another resident, Jackie Holley, wrote the following day: “My plants were covered in thousands of beetles, mostly on my crepe myrtles. This isn't just about having a beautiful garden, the amount of beetles was truly overwhelming. [They] were all over our cars and my teenage daughters saw them swarming over our yard.”
So far, Bernstein has been frustrated with how state and city officials have reacted in the wake of the unexpected insect migration, saying that they have not been forthcoming with information. "People are not really believing the authorities," she said, "because the authorities don't seem to know a whole lot about the situation they've created."
Located in Sellwood-Moreland, where the beetles have appeared, is the Oaks Bottom Wildlife Refuge, a 141 acre floodplain wetland located on the east bank of the Willamette River.
The beetles were first released 10 years ago in Oaks Bottom to combat purple loosestrife, a highly invasive plant that can infest wetlands and areas along rivers. The plant’s purple flowers might hold some visual appeal. But if purple loosestrife is left unchecked, it can take over thousands of acres, displacing native plants and threatening critical wildlife habitat, according to the U.S. Department of Agriculture.
Estimates from Oregon’s agriculture department say that the plant has the potential to cause $28 million in economic damages in the state.
Although Oregon has used leaf beetles to fight purple loosestrife since the mid-1990s, Oaks Bottom is the first place, that the state Department of Agriculture is aware of, where they were deployed on a broad scale in such close proximity to a residential area. In past years the beetle population at the refuge has died off due to flooding, but the insects became firmly established during 2013 and 2014.
The conditions that led to this summer’s extreme beetle population spike and the movement of the insects into Sellwood-Moreland were described by the agriculture department as “a perfect storm.”
Among the contributing factors the department pointed to were heavy purple loosestrife growth, which provided abundant food for the leaf beetles, water conditions that favored the insects, and out-of-the-ordinary weather. The entire state of Oregon, including Portland, is currently experiencing severe or extreme drought conditions.
The state Department of Agriculture said the beetles are not expected to reproduce on plants other than purple loosestrife, and that it is therefore unlikely the insects will be around for long in the residential areas outside of Oaks Bottom.
And because the beetles decimated the purple loosestrife in the refuge this year, the department also believes the insects should have less to eat in future years and that therefore “population explosions” like the one involved in the current “non-target mass feeding” probably won't happen again.
But Bernstein remains unconvinced. "Everybody in the neighborhood is really concerned that it could happen again next year if we have another warm winter and dry spring." she said. “The biggest concern I have is that climate change wasn’t factored into the decision of introducing these beetles into Oaks Bottom.”
Bill Lucia is a Reporter for Government Executive’s Route Fifty.
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