Go after the eggs first. One mass holds 30 to 50 eggs, so wrecking a single one in winter beats a whole afternoon of swatting in August. To kill spotted lanternflies, scrape the masses off the bark and drop them into alcohol or hot, soapy water. Then set a trap on the tree they crowd onto once the nymphs are out. Sprays come last, and a few of the common ones do more harm than good.
My first summer with them, back in 2019, I stood under a maple with a rolled newspaper and missed six times in a row. They do not lift off the way a fly does. A nymph loads up on its back legs and is several feet away before your arm finishes moving. The adults do the same thing, just heavier, and you hear them land.
That miss rate is the case for changing your timing instead of your swing. Hit an adult in August and you have removed exactly one insect. Scrape a mass off bark in February and you have taken out 30 to 50 before one of them hatches. Spotted lanternfly egg masses stay put from September through June, each one about 1 inch (2.5 cm) long, so you get ten months to work at your own pace.
Scraping alone does not finish it, because a mass that lands in the leaf litter can still hatch. USDA APHIS says to smash the eggs, then seal them in a bag with rubbing alcohol or hand sanitizer before the bag goes out. A container works just as well. Scrape straight down into hot, soapy water or a jar of hand sanitizer, held right under the mass so nothing gets away from you.
- September to June: Scrape every mass you can reach into hot, soapy water or a jar of hand sanitizer.
- Or smash and seal: Smash the eggs and bag them with rubbing alcohol instead, then put the bag in the trash.
- Summer: Put a circle trap on the trunk of whichever tree they crowd onto first.
- Leave alone: Your lawn, because this insect never lives in grass and never will.
Once the nymphs hatch and start climbing, trapping picks up what your scraping missed. A circle trap wraps the trunk and funnels the ones walking up into a container, and it keeps doing that while you are at work. Sticky bands do a similar job at a real cost. Left uncovered, they catch birds and squirrels and the bugs you want to keep, so any band you hang needs a screen over it. I prefer the circle trap on any tree kids walk past.
You can kill spotted lanternflies with a spray. It is still the last tool to reach for, and two mistakes show up over and over. Do not treat your lawn. This insect does not live in grass, so a lawn spray hits everything but the target. Skip broad pyrethroids too, since they kill bees along with the pest. If you spray at all, pick the least toxic product that does the job, and keep it off the plants while bees are working.
Home brew mixes from the internet are untested, which is reason enough to pass on them. Work the trunks instead, from the base up as high as you can safely reach, and go slower than feels necessary. A mass is only about 1 inch long, so the ones you miss are the ones you walked past too fast. Every mass you find in March is 30 to 50 fewer lanternflies in your yard by August. That is ten seconds of scraping, and no spray on the shelf matches it.
Read the full article: Spotted Lanternfly: What It Actually Damages
