The news that two spotted lanternflies were found in Willamette Valley nurseries worries some Oregon farmers, including wine grape growers who know the damage it causes. The two insects were found in the fall of 2020 and there have been no new sightings, according to Vaughn Walton, Oregon State University Extension Service horticultural entomologist and professor in the Department of Horticulture. He would like to see it stay that way.
“I don’t want to spend the last portion of my career dealing with another invasive insect,” said Walton, co-author of Spotted lanternfly is an invasive insect that may impact Oregon. “Early reports of spotted lanternfly are crucial to limiting its spread and the damage it does. People can help. They are our eyes for us. We can’t be everywhere.”
If one adult is sighted, more are to be found because they most certainly laid eggs, Walton said. The ODA quarantines and inspects imported plants for lanternfly, but there’s always the chance one will slip by.
Native to southern China, Taiwan and Vietnam, spotted lanternfly arrived in the United States in 2014 when it was found in Pennsylvania and now makes a home in nine states on the East Coast and Midwest. So far, there’s no known infestation in Oregon. If one establishes, Walton said, many of Oregon’s high-value industries may be affected, including wine grapes, nursery and tree crops, small fruits and timber.
The nymph stages of the spotted lanternfly have a healthy appetite for grapevines, hops and other fruit crops and also feed on a wide range of ornamental and woody trees. Piercing the plant stems and tree bark, the nymphs suck sap from young stems and leaves, weakening the plant. With a big enough infestation, photosynthesis is reduced and the plant eventually dies, costing hundreds of millions of dollars annually in lost agriculture, Walton said. If they don’t kill the plant, lanternflies produce honeydew, which attracts aphids and will cause mold to grow on Oregon-grown fruit, making it unsuitable for market.
Called a plant hopper because it doesn’t develop wings until adulthood, the quick-moving insects hatch in early spring from tiny eggs laid in September to mid-November and go through four nymph stages before reaching the adult stage in July through December. The nymphs, which range in size from ¾ inch to 1 inch, are black with white polka dots in the first three stages and add red in the fourth. As they grow, they split along their backs and crawl out into a new life stage. Finally, the adults emerge and set about mating and laying eggs until the first freeze kills them.
Spotted lanternfly is spread through human action. The tiny eggs are the life stage most likely to be transported and the most difficult to see, Walton said. Females lay at least two egg masses of 30 to 60 eggs in rows on any hard or smooth surface like trees, plastic yard objects, cars and trailers, grills and stone. The clusters are covered with a creamy white, puttylike substance that becomes gray as it dries and looks like lichen. With time, the covering turns tan and begins to crack, resembling a splotch of mud. Old egg masses look like rows of brownish seed-like deposits in four to seven columns, measuring roughly 1½ inches in length.
“The fact is, if you have movement of plants and good over very long distances, it’s inevitable that some insects get in,” Walton said. “That’s the price we pay for global trade.”
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Oregon State University