Green and Growing: This winter, look for spotted lantern fly eggs on trees
Perhaps the spotted lantern fly has escaped your attention, but the same may not be true a year from now.
These flying scourges were first identified in Pennsylvania in 2014. They quickly made headlines as they ravaged forests, farms, orchards, and vineyards there. These red, black and white destroyers spread to New Jersey, New York and the mid-Atlantic states. They were first spotted in locations around western Connecticut and central Massachusetts in 2019; Greenwich, Stamford, and New Canaan have established populations as of this writing. Spotted lantern flies have also been identified in Southbury and West Haven.
This winter, though, you can do something to limit their spread.
“Examine trees for egg masses,” says Dr. Victoria Smith, state entomologist with the Connecticut Agricultural Experiment Station. “Look at the trunks of maples, willows, walnuts, and all fruit trees. Spotted lantern flies like trees with sweet sap,” Smith says. “Above all, look at the tree of heaven (Ailanthus altissima).”
Ironically, the tree of heaven is the spotted lantern fly’s preferred host tree, though the insect will also lay eggs on maples, willows and many fruit trees. According to invasive plant experts, tree of heaven is one of our region’s most noxious landscape weeds. Talk about a double-whammy.
“Tree of heaven is frequently confused with our native sumacs, and they can be difficult to tell apart in winter,” says Dr. Smith. “But it has distinctive bark. People have compared it to the skin of a cantaloupe.” When you break a tree of heaven twig, she says, “you may experience a bad scent a little like kerosene.” Others have compared the scent to rancid peanut butter. (See the photos for more clues to its winter appearance.)
If you find suspicious egg masses, Smith recommends two actions. “First, take a photograph and send it with the location information to reportSLF@ct.gov. Second, remove the egg mass by scraping. You can use a putty knife, and old butter knife, an expired credit card, an ice scraper or anything that will remove the egg mass,” she says. “Be careful to not dig into the bark of trees you want to keep.”
The egg masses appear in two forms, one like a slurry of putty on the trunk. The other form lacks the “putty” covering, and the individual eggs are exposed as scales.
Peter Picone, a wildlife biologist with the Connecticut Department of Energy and Environmental Protection, has removed large tree of heaven infestations on conservation land. He suggests that you can identify tree of heaven’s presence any time of year, including winter.
In addition to the bark’s texture and its unpleasant odor, there’s another winter clue. Tree of heaven has both male and female trees. In winter, many female trees are visible because they hold seed clusters at the ends of branches.
One natural control for the tree is the Ailanthus webworm (Attiva aurea). The insect is present in southern New England but is not widespread enough to halt the tree of heaven’s spread.
Picone suggests that if you identify a tree of heaven this winter, mark the tree with paint or a ribbon.
“You can return to cut and remove tree of heaven any time of year,” he says. “But be prepared to monitor stump sprouts beginning in spring and new sprouts that appear independent of the original trunk.” The tree overtakes areas by sending underground runners as much as 100 feet from the main trunk.
Another removal method is to strip bark on the lower trunk. Many people are chagrined to learn that the next steps inevitably include herbicides.
“We don’t have a reliable non-herbicidal method for this killing this plant,” says Picone. Landowners can employ a licensed pesticide operator or use one of the protocols described on the Connecticut Invasive Plant Working Group’s site.
“By controlling invasive tree of heaven, you’ll also help control invasive spotted lantern fly,” Picone says. “That can be very rewarding.”
Should we monitor other insect pests this winter, as we did a few years ago for spongy moths (also known as gypsy moths)? “Most other insect pests, such as wooly adelgid and spongy moth, are at low levels now,” says state entomologist Victoria Smith. “They are unlikely to cause serious outbreaks this spring.”
Kathy Connolly writes about land care, landscape ecology and horticulture from Old Saybrook. Email her at Kathy@SpeakingofLandscapes.com.