The Spotted Lanternfly: one bad bug

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The rare and the not rare

Invasives are the opposite of rare. A third of all the vegetation in the northeast hails from Asia, according to native plant scientist Dr. Doug Tallamy.

What’s rare about invasives? The ability to stop them in their tracks.

A mantra among invasive geeks: controlling established invasives is maddeningly tough, but stopping them from becoming established in the first place is possible.

Most invasive plants we battle have been here a century or more. It’s rare we have a chance to catch an invader just getting started: in this case the Spotted Lanternfly (SLF).

The Spotted Lanternfly and its egg mass.

One bad bug

The Spotted Lanternfly (Lycorma delicatula) is “an exotic sap-feeding planthopper that has the potential to severely impact Connecticut’s agricultural crops, particularly apples, grapes, and hops, and ornamental trees” says the Connecticut Agricultural Experiment Station (CAES), which issued a statewide quarantine in 2021 and renewed it in January this year. The quarantine attempts to limit SLF by requiring inspection and notification of items in areas of infestation and prohibiting their movement without a “phytosanitary certificate” that documents the absence of SLF.

SLF stresses trees by puncturing bark and sucking sap. It also excretes a gooey “honeydew” that encourages sooty mold growth and attracts other insects. Adults can fly, but not far; most movement is via hitchhiking: laying eggs on a surface that is moved, usually by humans.

SLF is native to China, India and Vietnam. It is thought to have arrived in the US as egg masses on a shipment of stone. Maps show its malignant movement from discovery in 2014 northwest of Philadelphia. It radiated outward to 14 states since then, including much of New York. In Connecticut it followed rail lines into Fairfield and New Haven County towns. It’s been found in Massachusetts and in every county in Connecticut except Windham.

What does SLF like to eat?

The babies (nymphs) like Red Maple, Sugar Maple, White Pine, Red Oak and White Oak – about half the trees in Connecticut forests – and just about everything else as well.

As adults, their tastes become more refined. By late summer, they are focusing on their favorites: Tree of Heaven, grapes, and fruit trees.

Prime Host

SLF’s favorite food is the Tree of Heaven (Ailanthus altissima), a vigorous invasive tree that commonly grows in clumps along field edges and in open areas. Its leaves, smooth bark and growth pattern are similar to native sumac, though it grows taller and flowers differently.

There are at least four clusters of Tree of Heaven in field edges at Holcomb Farm, including a massive specimen in the hedgerow east of the farmhouse. Controlling Tree of Heaven is a challenge because cutting the trunk encourages underground roots to send up new trees 5, 10 or 20 feet away. Girdling (severing the living material under the bark of a mature tree all the way around) soon after new leaves have emerged, careful painting with herbicide, and attentive followup on popups yards away has proved successful, when done over several years.

Control and Report

We can all help make Spotted Lanternfly an invasive success story rather than an out-of-control disaster.

In April and earlier, look for egg masses on trees, rocks and other smooth surfaces like decks, houses and outdoor furniture. There are 30-50 eggs in a wide gray mass, bumpy, a few inches wide and long, covered in a gray waxy coating. Take a picture and report your finding to Crush it to bits and look for more.

When they hatch in May and June, nymphs feed on all kinds of young stems and leaves nearby. Look for groups – dozens of small, beetle-like black and, as spring turns to summer, larger and more red nymphs-clustering on trees and shoots. By late summer they are adult, gray and dull with folded wings when feeding but, aflight, easy to identify with spots and colorful rear wings. Take a picture and report your finding to  Then destroy the beetles.

If you like wine, fruit, trees, or Granby: keep your eyes peeled. If we all work together, we can keep Granby free of the Spotted Lanternfly.

More photos of the Spotted Lanternfly, maps, and links to more information are at

Granby residents tackle large projects together on regular 2nd Saturday mornings, and sometimes on weekdays as well. Send a note at to find out more.

Please join the Conservation Conversation about the Granby Public Library, April 10, 6:30–7:30 p.m.