Spotted lanternflies look like the photo on the left (the youngest nymph stage after eggs hatch) in the spring and early summer. Then they turn red with black blotches and white spots (middle photo) during the summer before maturing into the adult stage (right photo) in late summer and early fall.Penn State Extension

They’re back. Yes, those colorful but annoying insects known as spotted lanternflies are once again popping up in yards and gardens across New Jersey.

Although they’re only in the early phase of their life cycle — the nymph stage — experts seem to agree it’s never too early to snuff out any spotted lanternflies, or egg masses, that you might see.

Spotted lanternflies are invasive insects, feeding on the sap of their host plants, and leaving behind a sugary substance called honeydew that encourages fungal growth and new insects on the weakened plants. While they don’t pose any threat to people or pets, the lanternflies could cause serious damage to New Jersey cash crops like grapes, hops and ornamental trees, officials say.

This is the time of the year when these spotted bugs will start jumping through gardens, yards, parks and farms across the region. For now, they are tiny nymphs — only about a quarter-inch long — with black bodies, white spots and no wings.

Spotted lanternflies look like this during the youngest nymph stage after eggs hatch, usually in the spring and early summer. Then they turn red with black blotches and white spots during the summer before maturing into the adult stage.New Jersey Department of Agriculture

But later in the summer (mainly July and August) the lanternfly nymphs will turn red with black blotches and white spots. Then they will get bigger, grow wings and take to the air to swarm more trees and plants, just like they did last summer and fall here in New Jersey, as well as Pennsylvania, New York and other eastern states.

State officials have urged homeowners and business owners to destroy any spotted lanternflies and the insects’ eggs to prevent them from multiplying and causing damage.

Here are several important tips from the New Jersey Department of Agriculture and other experts:

State officials say the first step in the battle against spotted lanternflies is identifying the egg masses. If you see dark, sooty mold on a tree, rocks, fence posts or outdoor furniture, that is a sign that spotted lanternflies have been there.

The egg masses initially look like small spots of gray, putty-like material with a waxy coating. Over time, they can look darker, like dried mud on a tree. The egg sacs can also look like tire tracks.

Spotted lanternflies can deposit their egg masses on any trees or flat objects in your yard, although they favor the Tree-of-Heaven, a fast-growing tree that is native to Asia and common in New Jersey.

Experts recommend using a rock, a scraper or even an old credit card to crush the egg masses while you scrape them off the tree or other surface and into a bag — or even a second bag — to throw away. This prevents the eggs from hatching.

The egg masses can also be placed in a bag or container filled with a little bit of rubbing alcohol, bleach or hand sanitizer, and that will kill them.

The spotted lanternfly's egg masses initially look like small spots of gray, putty-like material with a waxy coating. Over time, they can look darker, look like dried mud on a tree. Amy Korman | Penn State ExtensionAmy Korman | Penn State Extension

The most proven way of killing a spotted lanternfly is to squash it. A quick stomp or a swift swat is the most efficient way to deal with the problem. Just keep this in mind — sometimes this can be a little tricky because the bugs are quick to move out of the way.

If you have a tree that seems to be a magnet for spotted lanternflies, turn it into a trap for the bugs by wrapping the trunk in a sticky band, which is commonly sold in garden stores. Be sure to take measures like putting a wire or mesh cage around the trap to prevent other animals, like birds and squirrels, from getting hurt.

Tree bands are most effective when spotted lanternflies are still nymphs and haven’t yet grown wings, according to the state agriculture department.

Bug experts from the Penn State Extension say you can also build your own inexpensive “circle traps,” which are funnel-style traps that can be wrapped around tree trunks. They are designed to capture lanternfly nymphs as the critters crawl up the tree to feed on leaves.

“This new style trap is made of plastic-coated insect screening and does not use any sticky material at all. It is basically a tunnel that SLFs walk into,” the Penn State Extension notes in this fact sheet. “When they move upward in the trap, they end up in a dead-end collection container where they die.”

Many common spray insecticides that kill bugs on contact have proven effective against spotted lanternflies, according to state officials.

But using insecticides should be done with extreme caution. Many of the chemicals used in insecticides are also considered highly toxic for bees, the critical ecological pieces that pollinate so many of the plants around us. Make sure you read the labels and do your research before wantonly spraying any insecticides.

There are some exceptions. One way of dealing with spotted lanternfly eggs is by using horticultural oils commonly sold at garden stores, which do not typically affect other species.

This is what adult spotted lanternflies look like in the late summer and early fall, with their wings open.New Jersey Department of Agriculture

In some cases, chemicals can be injected into or onto trees to make them toxic for spotted lanternflies. It’s similar to how tick prevention medicine works for dogs. Property owners interested in having their trees treated should contact a qualified arborist.

The state agriculture department strongly recommends that property owners remove any Tree-of-Heaven they can. Other host plants preferred by lanternflies, such as wild grape and oriental bittersweet, should also be removed, if possible.

This is what adult spotted lanternflies look like in the late summer and early fall, with their wings closed.New Jersey Department of Agriculture

Note: Some of the material in this report was originally published on NJ.com in August 2021 and February 2022.

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Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com.

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