Not saying/suggesting to use this directly on your pennants but you might want to try it on your carpet and other places in the house?
We've been using it for quite a few years, especially at our trailer, to keep spiders and other bugs away from our awnings, doors/screens and shed.
It isn't toxic and can be used indoors and out. We've found, even during rain, it lasts at least a couple months or longer.
https://www.glasshousenursery.ca/products/bugtek
https://sani-depot.ca/en/product/itp-bugtek-2/