Anthony Vietri has learned a lot about the spotted lanternfly over the three seasons he’s dealt with the invasive pest in his Pennsylvania vineyards. “They are an exasperating but fascinating insect,” says the owner and winemaker of Va La Vineyards. “As adults, they have the quite annoying habit of jumping onto things as they pass—cars, animals and, unfortunately, your face.”
The spotted lanternfly is a piercing, sucking insect that feeds on plant sap, making them a major threat to fruit crops and trees. Black with white spots, they develop bright red hind wings as they age and are fairly easy to identify. While the behaviors of the insect are better understood now than when they were first found stateside, wineries are still figuring out the best approach to protect their vines from the invasive species.
Since spotted lanternflies were first detected in Berks County, Pennsylvania in September 2014, infestations have been reported in 11 states, according to the USDA, including New Jersey, New York, Delaware, Maryland, Virginia, Connecticut, Massachusetts, Indiana, Ohio and West Virginia. Vineyards in these states have suffered vine damage, as well as lost yields and revenue, as a result of these infestations.
“They can be extremely irritating to outdoor visitors at tasting rooms,” says Vietri. He points out how much of a nuisance the jumping bugs are during events like weddings. “And much worse, they are sap-feeders that will destroy vines if they infest in large numbers.”
Native to Asia, the spotted lanternfly is primarily known to feed on the Tree of Heaven, but has a wide host range, including apples, cherries, hops, plums and grapes. They produce one generation per year, explains Michela Centinari, an associate professor viticulture at Pennsylvania State University, which is leading spotted lanternfly research and public outreach efforts to fight the pest.
Adult spotted lanternflies lay their eggs in the fall. The egg masses, which can hold 30–50 eggs each, can survive cold winter temperatures, even after most of the adults have frozen to death. Depending on how warm a region’s spring is, they emerge as nymphs sometime in early or late May. That’s when, says Centinari, populations are easiest to control.
“Typically, that’s when growers have to spray for Japanese beetles and a lot of other pests, and can kill the lanternflies because they don’t fly, they just jump around,” she says. “The problem is when they turn into adults, usually in July.”
At that point, they’ve run out of food sources in wooded areas, and begin moving into the outer rows of nearby vineyards at the beginning of August. They take up residence in the canopy and like to feed on the stem, sucking sugar and nutrients that should otherwise be going to the grapes at a pivotal time.
“Luckily, they are very susceptible to most insecticides, which at this point is our only line of defense,” says Mike Beneduce, vineyard manager and winemaker at Beneduce Vineyards in Pittstown, New Jersey. He saw the first wave of spotted lanternflies hit his vineyard in 2019. Unfortunately, when the adult insects are most active, in August and September, is also when harvest kicks off, making it difficult to spray pesticides to combat them.
The best way to kill adult spotted lanternflies is by smashing or stomping them, which isn’t difficult. While they may be good at hopping, they aren’t very good at flying. But that requires a lot of labor at an already labor-intensive part of the year for winemaking.
“As far as eradication, well, we feel that you can’t really,” says Vietri. “We are dedicated to organic controls, and none of those work so far that we can see.” But even if vineyard workers eradicate the spotted lanternfly completely on their own property, it’s only a short time before the pest finds its way back from other surrounding properties.
Some vineyards are trialing other approaches to manage spotted lanternfly populations. Unionville Vineyards in Ringoes, New Jersey first noticed the bugs in their vineyards late in the 2019 season, and has since introduced an insecticide spray to their regular post-harvest fungicide application—an additional cost to their operations.
This spring, the winery will introduce chickens to the vineyards. “We hope they will eat up pests in the nymph and larval stage before we have to contend with them as adults,” says John Cifelli, the vineyard’s general manager.
In Pennsylvania, Vietri collects praying mantis nests from vines every winter during pruning, then reintroduces them into the vineyards later for insect control. “While we have a really lovely population of mantis, and they love to eat spotted lanternflies, they cannot make any discernible dent in the huge populations,” he says.
Beneduce remains hopeful. “I might be overly optimistic, but my hunch is that much like the invasives that came before them, such as Japanese beetles and Brown marmorated stink bugs, they will eventually come into balance with their new surroundings,” he says.
For wine regions that have yet to experience spotted lanternfly infestations, prevention is key. While no live populations of spotted lanternflies have yet been found in California, the state’s department of food and agriculture is already training county agricultural personnel, as well as staff at border inspection stations and ports of entry, to identify and combat the pest.
In the meantime, Vietri and other winemakers on the East Coast are learning to live with them. “We know they are coming. We cannot completely stop them,” he says. “If we can keep the population in check, and our vines happy, then we will survive to grow again.”