—by Matt Milkovich

As spotted lanternfly (Lycorma delicatula) continues to migrate outward from its Mid-Atlantic epicenter, a loose network of government, industry and university groups is attempting to track the invasive planthopper, slow its spread and give grape growers and researchers more time to develop effective management tactics.

Recent findings in Michigan and California show that the efforts are working.

First found in the United States in Pennsylvania in 2014, spotted lanternfly (SLF) feeds on grapevines, among many other hosts, and contributes to long-term vine decline.

In June, a small population of juvenile spotted lanternfly was found in Michigan, the second SLF finding in the state. Neither finding was made in Michigan’s fruit-growing areas. The most recent infestation was detected through monitoring traps deployed by Michigan State University, as part of a collaboration with the Michigan Department of Agriculture and Rural Development and the U.S. Department of Agriculture, according to a news release.

In March, staff at California’s Truckee border protection station found SLF egg masses on a shipment entering the state. According to the California Association of Winegrape Growers (CAWG), the egg masses were intercepted on a 30-foot-tall metal art installation originating from New York. Dead spotted lanternflies have been found on airplane shipments, but the Truckee finding is the only live SLF finding in California so far, said CAWG President Natalie Collins.

The shipment was rejected and returned to Nevada, where officials found additional egg masses in previously inaccessible areas. There, they power-washed the artwork with hot water and detergent. The shipment was returned to the Truckee station and released to its destination in Sonoma County under a warning notice. With the owner’s permission, county staff opened the art installation and found three additional egg masses. They concluded the inspection after they were confident no more egg masses remained, according to CAWG.

Spotted lanternfly poses a particular threat to wine grapes in California, where 615,000 vineyard acres produce 80 percent of U.S. wine. Among the state’s wine grape growers, there’s a “feeling that it’s not a matter of if, but when” SLF arrives in their vineyards, Collins said.

“Hopefully, we can push it out further, but we’re trying to make sure we are prepared if (SLF) does establish itself here,” she said.

Many California counties are taking proactive measures such as removing tree of heaven, one of SLF’s preferred host plants. At California’s agricultural border protection stations, like the one in Truckee, staff have been trained to identify SLF’s different life stages, including its mud-like egg masses, Collins said.

CAWG uses grower assessments to fund SLF research and mitigation. Announcing the recent SLF finding is part of its mitigation efforts. The association wants the public to know what SLF looks like, the potential harm it can do to California’s wine industry, and what people should do if they find the invasive pest, she said.

California residents are encouraged to “Snag it. Snap it. Report it.” In other words: Capture the insect if possible, take a picture and report the finding to the California Department of Food and Agriculture.

States with established SLF populations encourage the public to “stomp it out” if they find it, but California wants to verify that it’s SLF and respond rapidly to the area where it was found, Collins said. •