In CT, we are supposed to kill them on sight.

I believe your supposed to kill them no matter where you are located!

Kill them!

I watched some videos on the spotted lanternflies and none suggested chemical pesticides on the little suckers and I don't know why, but I do suggest you use it on your maple. I use Permethrin which is a synthetic Pyrethroid as my go to pesticide and it should kill the laternflies and their nymphs. The only thing it won't kill for me is adult Colorado beetles but I do use it to control many other bugs and one spray will last for many weeks

and isn't hard to find. Below is from the EPA

" Permethrin has been registered by the EPA since 1979. It is currently registered and sold in a number of products such as residential indoor and outdoor insect foggers and sprays, treated clothing, flea products for dogs, termite treatments, agricultural and livestock products, and mosquito abatement products. It is also regulated by the Food and Drug Administration as a treatment of head lice and scabies. Permethrin is the most widely used mosquito adulticide in the U.S. and is used to treat 9 to 10 million acres annually (out of 32-39 million acres treated with a mosquito adulticide). Permethrin’s widespread use can be attributed to its low cost, high effectiveness, low incidence of pest resistance, and broad labeling."