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If you have crickets in your crawl there probably Camel Crickets. Camel crickets eat only mold. So Camel Crickets=Mold.
The little black dots you see spotting your beams are hardened cricket poop. Sorry about the bad news but my goal is to inform and not sugar coat. Frogs and Mice love a Cricket meal. And aweful enough snakes eat the mice and frogs.
So under your home is an ecological zoo. But dont be dismayed … its everybody.s home who has a vented crawl space.