Hello Barbara,

This is an excellent - and timely - question as you want to get a handle on these ASAP. Not knowing what plants/trees/grapevines you have seen the spotted lantern flies on, I can provide general guidance. For more specific plants, please provide photos. In general, note that these are of nuisance value to plants, rather than destructive. So spraying insecticides is generally not recommended - particularly as these also target the beneficial insects and pollinators that we want to attract to our gardens.

1. Remove eggs: Using a plastic credit card, paint scraper, etc., scrape off egg cases on and near the grape vine into a container. Also check nearby surfaces & trees. Then cover the eggs with rubbing alcohol, then discard.
https://extension.psu.edu/spotted-lanternfly-management-in-vineyards

2. Remove any Tree of Heaven on your property, Ailanthus altissima, which is an invasive plant & a preferred SLF host. It has some native tree lookalikes some as Black Walnut & Staghorn Sumac. Feel free to send photos for help distinguishing, and here is a link with details: https://extension.psu.edu/tree-of-heaven-native-look-alikes

3. Monitor other plants over the season. Spraying nymphs off the plants is an effective control. In our humid climate it is advisable to spray down early in the day so that leaves can dry off before evening. Avoid leaving grape vines damp.. Knocking nymphs into a container of water (with a few drops of Castile liquid soap to break water surface tension) then covering with a lid to prevent escape can help chedk population growth. Anecdotally, some gardeners have found small portable hand vacuums useful for catching nymphs, then dumping into the soapy water to drown.

4. Make (or even buy) and deploy SLF traps on your grapevine trunk if on an arbor, trees, etc., that have screening to prevent accidentally catching birds and other beneficials, to prevent SLF nymphs from climbing up into your grapevine. https://extension.rutgers.edu/spotted-lanternfly/management-trapping

5. Plant a border of flowering natives and herbs to attract beneficials, such as insect predators to your yard.

6. Additionally, there are reports of birds feeding on SLF, so maintaining a clean birdbath during the day could serve to attract birds to your yard. I would recommend emptying the birdbath at dusk & refilling in early hours to prevent rats taking advantage of the water source. If you have the budget for it, one of those invisible ponds with a fountain on a timer/solar pump can provide water during the day, but not at night. 

7. If you're not squeamish, simply squash them and drop them into a container of water with a bit of dish soap in it.

Resources:

https://extension.psu.edu/spotted-lanternfly-management-guide

https://mda.maryland.gov/plants-pests/Pages/spotted-lantern-fly.aspx

https://extension.umd.edu/resource/spotted-lanternfly-home-gardens/

I hope this helps you deal with these bugs! Let us know if you want further information or help.

Lesley for UDC master gardener volunteers.