Hi, 

We don't recommend using any insecticide to treat the nymphs. Smashing can help or we have heard of people using small hand vacuums to suck them up and they tend to die pretty quickly with out a food or water source. 

Using a pesticide would end up harming beneficial insects in the process since there isn't a targeted pesticide just for Spotted Lantern Fly. 

Mature healthy trees will be fine though. We have noticed that despite their quick reproduction and boom in population, they tend to not kill most trees, but can produce some "honeydew" - a sticky excretion they produce. If it isn't near a car or outside seating area like a deck or patio you shouldn't be bothered by it. 

You can read more information on our website which has recommendations for reporting, treating if needed and overall management. It also has additional links to the Maryland Department of Agriculture as well as other sites that may help. 

Let us know if you have further questions. 

Emily