State Watch

Invasive insect may threaten California’s wine grapes

A spotted lantern fly crawls along the dirt at PNC Park during a baseball game between the Pittsburgh Pirates and the Washington Nationals, Friday, Sept. 10, 2021, in Pittsburgh. (AP Photo/Keith Srakocic)

The spotted lanternfly may reach several wine-producing counties in California, putting the fruit and other crops at risk of being destroyed, as the invasive insect spreads across the United States.

A new analysis from North Carolina State University released Wednesday has revealed that the spotted lanternfly, an invasive insect native to Asia, has a chance of first reaching wine-producing counties of California in five years.

“This is a big concern for grape growers; it could lead to billions of dollars of losses in the agricultural sector,” the study’s lead author Chris Jones said in a news release. “With this study, we have a baseline that we can use to evaluate the effect of different management strategies.”

California produces 82 percent of the nation’s grapes.

The study used observations gathered by state and federal agriculture, as well as pest experts, between 2015 and 2019 and considered railroad networks as a “high risk” for insect transportation. The spotted lanternfly is known to lay its eggs on many different surfaces, including vehicles.

The insects also look for the tree of heaven, a species of tree that hosts the invasive species.

“We assumed that the spotted lanternfly needs tree of heaven to complete its life cycle,” Jones continued. “The presence of tree of heaven, along with rail networks, seem to be two factors that could drive spread to California. The temperature there is relatively suitable across the state.”

It was previously seen throughout Pennsylvania counties since 2014 and attacked plant life and crops in the counties, with the Pennsylvania Department of Agriculture even calling for citizens to kill them on sight.

It has since spread to at least 11 other states, according to the study.

“It’s hard to say in advance exactly what the spotted lanternfly’s impact will be on the grape-producing regions of the West Coast, since we only have data from cold-producing regions,” Jones added. “In Pennsylvania, we’ve seen vineyard losses from the double whammy of cold and from spotted lanternflies feeding on the vines. But we do know producers can also experience losses because of the mold growth alone.”

The insect is detrimental to plant life and crops because it can damage and destroy grapes, apples, almonds, walnuts, cherries, hops, peaches and certain trees by directly feeding on them. The species also leaves behind a residue known as “honeydew” that aids in mold growth.

“We hope this helps pest managers prepare. If they can start early surveillance, or start treating as soon as the spotted lanternfly arrives, it could slow the spread to other areas,” Jones said. “They could also pre-emptively remove tree of heaven around vineyards.”

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