Have you seen the forum-made tutorials for things like spiritual hygiene, developing your astral senses and avoiding impostors and parasites?
I suggest browsing through all the linked posts therein, and that will give you a road background of techniques that you can choose from for what’s right for you.
Larvae though are not parasites, as far as I know - they are kind of like leech-looking things that exists to clean up old discarded energy. They are not malicious and aren’t attacking, but if you have leaks in your energy body, they can get attached by mistake. The best way to avoid them is do energy work to ensure your energy body is intact, whole and not leaking. But if you get any they are easy to pluck off. Don’t kill those as they are like beneficial insects that perform a useful function.