January 27, 2023

Some people compare the bark of the sky tree to the skin of a honeydew melon. (Photo by Kathy Connolly)

The Tree of Heaven has male and female forms. Females are easy to see in winter as they cling to their flower spikes, which house thousands of seeds. (Photo by Kathy Connolly)

Adult spotted lanternflies lay eggs from August to November. Most egg masses have a light, putty-like coating that turns brown over time. See the mass on the left. (Photo: Luke Hearon, CC 2.0)

Spotted lanternfly eggs sometimes appear as scales on tree bark. They are pictured here on the celestial tree, one of the insect’s main hosts, but they also lay eggs on the trunks of maples, willows and many fruit trees. (Photo: Lawrence Barringer, Bugwood.org, CC 3.0)

Perhaps the spotted lanternfly has escaped your attention, but in a year that may not be the case.

These flying flagella were first identified in Pennsylvania in 2014. They quickly made headlines when they devastated 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 sighted in 2019 in locations in western Connecticut and central Massachusetts. Greenwich, Stamford, and New Canaan have established populations at the time of this writing. Spotted lanternflies have also been identified in Southbury and West Haven.

However, this winter there is something you can do to limit its spread.

“Examine trees for masses of eggs,” says Dr. Victoria Smith, state entomologist at the Connecticut Agricultural Experiment Station. “Look at the trunks of the maples, willows, walnuts and all the fruit trees. Spotted lanterns fly like sweet sap trees,” says Smith. “In particular, look at the sky tree (Ailanthus altissima).”

Ironically, the Tree of Heaven is the spotted lanternfly’s preferred host tree, although the insect also lays eggs on maples, willows, and many fruit trees. Tree of heaven is one of the most damaging landscape weeds in our region, according to invasive plant experts. Talk about a double whammy.

“Heaven’s tree is often confused with our native sumacs, and they can be difficult to tell apart in winter,” says Dr. Smith. “But it has a distinctive bark. People have compared it to the skin of a honeydew melon.” If you break a branch of the sky tree, she says, “You can smell a bad smell that’s a bit like kerosene.” Others have compared the scent to rancid peanut butter. (See the photos for more clues to his winter appearance.)

If you find suspicious masses of eggs, Smith recommends two actions. “First take a picture and send it to [email protected] with the location information. Second, remove the egg mass by scraping. You can use a spatula and an old butter knife, an expired credit card, an ice scraper, or anything that will remove the egg mass,” she says. “Be careful not to dig into the bark of trees you intend to keep.”

The egg masses appear in two forms, one like a slurry of putty on the stem. The other form lacks the “putty” shell and the individual eggs are exposed as scales.

remove sky tree?

Peter Picone, a wildlife biologist with the Connecticut Department of Energy and Environmental Protection, has cleaned up a large tree of heaven infestation at wildlife sanctuaries. He suggests that you can identify the presence of the Tree of Heaven at any time of the year, including winter.

In addition to the texture of the bark and its unpleasant smell, there is another wintry clue. The Tree of Heaven has both male and female trees. In winter, many female trees are visible because they bear clusters of seeds at the ends of the branches.

A natural control for the tree is the Ailanthus webworm (Attiva aurea). The insect is found in southern New England but is not widespread enough to stop the tree of heaven from spreading.

Picone suggests that if you identify a Tree of Heaven this winter, mark the tree with paint or a ribbon.

“You can come back year-round to cut down and remove the Tree of Heaven,” he says. “But be prepared to monitor stump sprouts beginning in spring and new sprouts appearing independent of the original trunk.” The tree overtakes territory by sending out underground runners up to 100 feet from the main trunk.

Another removal method is to strip bark off the lower trunk. Many people are saddened to learn that the next steps inevitably involve herbicides.

“We don’t have a reliable nonherbicidal method to kill this plant,” says Picone. Landowners can hire a licensed pesticide operator or use one of the protocols outlined on the Connecticut Invasive Plant Working Group website.

“By controlling the invasive sky tree, you also help control the invasive spotted lanternfly,” says Picone. “That can be very enriching.”

Should we monitor other insect pests this winter like we did with sponge moths (aka gypsy moths) a few years ago? “Most other insect pests, like woolly adelgid and sponge 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 management, landscape ecology and horticulture from Old Saybrook. Email her at [email protected]

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