It’s not a butterfly. It’s not a moth. And, despite its name, it’s not even a fly. Liz Magnuson, the Wolff’s Apple House Annuals Manager, describes Spotted Lanternfly as more like a leech that attaches itself to trees and other plants.
And once it is there, the leech-like plant hopper “causes serious damage in trees,” says the Pennsylvania Department of Agriculture, “including oozing sap, wilting, leaf curling, and tree dieback” (meaning the branches begin to die and the tree itself could die within a year or two). Not only that, “when spotted lanternflies feed, they excrete a sugary substance, called honeydew, that encourages the growth of black sooty mold. This mold is harmless to people, however it causes damage to plants.”
That’s bad news for fruit trees, roses, grape vines, silver maples, sugar maples, holly trees, tulip magnolias, black walnut trees, and many other plants throughout southeastern Pennsylvania.
And the problem is not going away. In fact, in Delaware County, reports of Spotted Lanternfly sightings have increased 500%. This could be because people are home more often, says Liz, but she adds that it’s also consistent with what Wolff’s has seen this year. However, Spotted Lanternfly mostly live in the trees, rather than venturing onto the produce or the plants. While customers might find one or two on a plant in the garden center, the insects don’t swarm like yellowjackets on fruit–no matter how many there are.
What Is Wolff’s doing?
Wolff’s is doing all we possibly can to combat the spread. Unfortunately, pesticides that kill the invasive pest most effectively can also decimate the local ecology, including birds, fish and beneficial insects, so Wolff’s is careful to avoid this.
Two other options make use of the nymph lanternflies’ behavior patterns, and you can use these options at home. Nymphs like to eat the leaves of trees, but it’s easy for the wind to blow them out of the trees. They then walk up the tree trunks to get back to the leaves. So we try to catch them as they climb by using:
- Sticky tape (fly tape wrapped around trees). We cut it in half to make it less wide, so it catches the lanternflies as they climb but decreases the risk that birds and small mammals will get stuck to it.
- A circle trap. This is a really effective way to target just the Spotted Lanternfly and not birds or butterflies, since birds and butterflies do not climb trees. “It is basically a tunnel that SLFs walk into,” according to the Penn State Extension, which provides instructions for creating circle traps.
The other way we’ve decreased the Spotted Lanternfly population is by removing its favorite food source! Spotted Lanternflies love to eat the leaves of the Tree of Heaven. We’ve removed the host trees, but we’ve had to do so very carefully.
Like the Spotted Lanternfly, Tree of Heaven is invasive, so one would think removing them would be top priority. That would be nice, but there’s a small problem. If you cut one tree down, 500 new trees will take its place. Instead, you have to cut into the tree and poison it first. (There are currently about a million by the plant office, says Liz.)
Another drawback to removing Tree of Heaven? “They are so insinuated into our environment,” says Liz. She counts hundreds just on her short drive to work. And many of the trees aren’t on people’s property, where they could remove them–they’re in common areas or government-owned space.
In addition to carefully removing many of the trees, we also worked with a consultant from Bartlett Tree Experts who helped us turn one Tree of Heaven host tree into a “bait tree,” by doing a “root drench,” which pulls an insecticide up through the tree and is targeted to kill the Spotted Lanternflies as they devour it. This isn’t an environmental hazard, but the process was expensive, so it may not be an option for individual homeowners. However, Liz says this is an important step business owners should consider taking to decrease the spread.
With the marked increase in Spotted Lanternfly in our area this year, we’re using multiple strategies to stop the spread. We hope that some of these strategies will work for you, as well, and you can always feel free to ask us if you have questions!