https://phys.org/news/2021-01-rnai-based-products-sustainabl...
Still more development to be done, but there are alternatives to existing synthetic pesticides on the horizon.
However, the active ingredient, double-stranded RNA, is ubiquitous in nature without obvious adverse impacts. It degrades very readily. It doesn't impact gene expression in mammals, even if completely homologous to a transcript (which is why in contrast to synthetic short interfering RNAs there's no obvious use as a therapeutic). It's an extraordinarily narrow spectrum approach, which is quite different to anything in the past, and why the approach is receiving a lot of interest and investment.
There's ongoing synthesis of data on environmental impacts. Have a read: https://www.oecd.org/officialdocuments/publicdisplaydocument...