Both the MDA and UMD Extension do not recommend the use of insecticide to manage Spotted Lanternfly (SLF). Not only will an insecticide not work for very long, or very thoroughly, but the bulk of the SLF population is out of our reach anyway, feeding and/or laying eggs in treetops that those sprays will not affect. Additionally, there is no SLF-specific insecticide; all have the potential to affect other insects if sprays contact them directly (or, for certain insecticide ingredients, if the dried residues contact them as well).

As the page linked above mentions, lower-toxicity options like insecticidal soap or horticultural oil can work if absolutely necessary, but only on the SLF the spray actually coats during its application. Those that jump away or wander back into the treated area later will be unaffected. Since the nymphs do not cause serious plant damage, they may be a nuisance to have around, but are not harming the plants. (If you are growing grapevines in particular for wine-making, high populations might cause problems for the harvest, but even then, research hasn't been conclusive on this.)

Miri