A single scale insect discovered in an Oregon vineyard last month was determined by scientists at Oregon State University not to be the harmful and highly invasive pest vine mealybug.
Although the exact species of the exemplar is yet to be defined by DNA testing, it was most likely a ground or obscure mealybug. Testing was performed in collaboration with the University of California at Berkeley.
This does not mean that Oregon grape growers are off the hook, however. Vaughn Walton, horticultural entomologist at OSU, said that other mealybug species may also transmit grapevine leafroll virus, which inhibits ripening and affects yield when left unchecked in vineyards.
“Other species have not been known to be as invasive as the vine mealybug,” Walton told Wines & Vines. “That doesn’t mean these other species are not important, or that they can’t also transmit viruses. I’ve heard reports of other vineyards that have not spotted VMB, but still have leafroll virus. There are other species of scale insects with very cryptic lifestyles. Few growers notice them until there is a real problem.”