About two years ago I read up on chitin as a possible pest control/deterrent as I was always struggling with mealybugs and thrips, especially in spring, and buying IPMs was getting quite expensive.
I had the most problems with my banana tree (thrips) and my kumquats (mealy bugs). But since I added insect frass (in my case sheddings and droppings from zophobas) in the fall two years ago, this problem disappeared almost miraculously. Since then I have added a small handful every spring and haven't seen a single thrip or mite on any of my plants.
Sooo… idk, it definitely gets a "worked for me".
But since this is still an area of active research (albeit with growing evidence), I think it's important to describe my setup as it may affect any results:
All my plants live in unglazed terracotta with varying mixtures of mostly pine bark, perlite, some organic material such as worm castings and a pinch of diatomaceous earth. You may recognize this as a common "diy aroid mix". I also feed organically and keep the pots slightly moist at all times to keep everything biologically active (as evidenced by the substrate eating my wooden skewers every few weeks).
The plants are: a cherimoya, kumquats, figs, a banana, two monsteras, and a bunch of pitahayas (although the cuttings are only 1 year old and haven't found a permanent home yet), hoyas and a small pineapple.
Looking forward to hear everyones experiences with this!