CHAMBERSBURG, Pa. — Your Franklin County landscape may be harboring some invasive pests. Now is a good time to scout and consider options for managing these interlopers.
Egg masses of the invasive insect, spotted lanternfly (SLF), can be found on tree trunks and many other protected surfaces during the winter months. Each egg mass contains anywhere from 30 to 50 eggs; the female lays the eggs in the fall and then covers them with a flat smear of a gray-brown substance that weathers to a tan, gray, or brown mud-like appearance.
Preferred host trees include red maple, silver maple, and willow. Other trees, as well as other protected surfaces such as rocks, decks, outdoor furniture, and fences, may also be used by the females for egg laying.
If you find SLF egg masses, you can scrape them from surfaces into a solution containing alcohol, such as rubbing alcohol or hand sanitizer, or you can thoroughly smash the eggs to kill them. The Franklin County Extension office has free scraper cards which you can use to scrape eggs – stop in and ask for one.
You will not be able to reach all the egg masses deposited on a tree – most of them will be too high to safely reach – but you can scout tree trunks and other likely surfaces close to ground level, especially if you found SLF adults in your landscape last fall.
Should you use insecticides to spray egg masses? That’s not recommended, as the insecticide is unlikely to penetrate the hard mud-like coating, and you could harm other beneficial organisms. Researchers are investigating the use of oils to smother egg masses, but more research is needed on this topic. Although you can try spraying egg masses with a dormant rate application of horticultural oil, following label directions, it may not penetrate to kill the eggs, and there is the potential of damage to tree buds from the oil. So, it’s currently not a very effective strategy.
Should you hire an arborist to scrape egg masses? Again, this is not recommended, as the egg masses are so randomly scattered and so difficult to find in the canopy of a large tree, it would not be an effective use of your money or the arborist’s time.
Each egg mass destroyed means up to 30 to 50 fewer SLF insects emerging later this year, so that’s a good thing. However, you may still find SLF in your landscape that have emerged from intact egg masses, so you may need to use other strategies during late spring and summer months to manage SLF nymphs and adults.
For more information on identification and management of SLF, visit the Franklin County Extension office for a free copy of Penn State Extension’s “Spotted Lanternfly Management Guide” or visit the Penn State Extension website at https://extension.psu.edu/spotted-lanternfly.
–Annette MaCoy, Penn State Extension
