Fall is the time to scrape spotted lanternfly egg masses into rubbing alcohol, URI says

Spotted lanternfly females are laying egg masses on trees, fence posts and parked cars across southern New England right now, and entomologists at the University of Rhode Island say the cheapest way to blunt next summer’s swarm is to destroy those eggs before they hatch. The laying season runs from September through December. A gray or brown smear about an inch long is the telltale sign, and URI’s advice, issued October 14, is to scrape it into rubbing alcohol or hand sanitizer.

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The urgency comes from how the summer of 2026 went. The insect was widespread across New England and especially abundant in the southern part of the region, and its numbers keep climbing as people unknowingly carry it along on vehicles, equipment and other materials. Egg masses stay dormant through winter, so the fall and winter months are the stretch when a homeowner can act directly against a pest that is otherwise hard to control.

How to scrape a lanternfly egg mass

Lisa Tewksbury, an entomologist who directs URI’s Biocontrol Lab, told readers in a question-and-answer feature distributed through Newswise that managing eggs is the best approach, because every mass removed reduces the feeding by nymphs and adults the following spring and summer. She and research assistant Dana Terrill answered reader questions about identification and removal. Egg masses are most often found on tree bark, though they also turn up on cars, outdoor furniture and fence posts.

The recommended tool is any hard, flat edge, such as an old credit card or putty knife. The mass is scraped directly into a container of rubbing alcohol or hand sanitizer, or it can simply be squashed. The mud-like covering protects the eggs from predators, drying out and cold, although it sometimes wears away and leaves the rows of eggs exposed. Timing matters because nymphs typically emerge in May and June, so the work should be finished before then.

Spongy moth egg masses look similar but are tan rather than gray, and spongy moth is also an invasive species, so squashing one by mistake does no harm. The federal government gives matching guidance: in a USDA announcement asking residents to look for egg masses, Matthew Travis, the national policy manager for the spotted lanternfly at the Animal and Plant Health Inspection Service, urged people to remove them to keep them from hatching in the spring. USDA suggests crushing and scraping the eggs into a plastic bag, sealing it and putting it in the trash.

Why southern New England is a hot spot

Rhode Island’s own history shows how quickly the insect has settled in. According to URI’s spotted lanternfly distribution page, a single adult found in Warwick in August 2021 was the state’s first detection, and a second adult turned up in Smithfield in 2022. USDA staff later found clusters along Route 7 in Smithfield that confirmed the first Rhode Island population. Nymphs jump and adults fly short distances, but human activity does the most to spread them.

By early September, television station WJAR reported in a story on vineyards bracing for the insect that the Rhode Island Department of Environmental Management considers it established in all five counties. The insect’s preferred host is the invasive Tree of Heaven, and it also threatens vineyards and orchards. Verde Vineyards owner James Verde said his Johnston property has been largely spared because no tree-of-heaven grows nearby, while Newport Vineyards owner Paul Nunes said the pest had not yet reached his vineyard.

Oil sprays, vacuums and biocontrol

Scraping is not the only option for property owners. Horticultural oil can be applied to egg masses during the dormant season, ideally between February and April, or a pest management professional can be hired to do it. For nymphs and adults, a rechargeable handheld or backpack shop vacuum works, as do circle traps that funnel insects climbing a trunk into a collection container. Birds and praying mantises also eat the insects, though not enough to stop an outbreak.

One instruction runs against instinct: infested trees should not be cut down. Lanternflies swarm and move to neighboring trees in search of food, so felling a tree can scatter the problem rather than end it. Longer term, the URI Biocontrol Lab is one of seven USDA-approved sites in the United States working on spotted lanternfly biocontrol. USDA is evaluating a parasitoid wasp, a process the university says could take a few more years, which leaves hand removal as the main defense for now. WJAR reported that URI is studying Dryinus sinicus, a parasitoid wasp from China that attacks lanternfly nymphs, and that no biological-control agent is yet approved for release. Heavy infestations can weaken grapevines, cut yields and leave plants more vulnerable to cold, and the sticky honeydew the insects excrete can encourage sooty mold, so a few minutes with a scraper this fall can pay off well beyond the backyard.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.