It should bloom on any damp cool organic material out of sunlight, if it's active. It goes dormant pretty much above 90f or low 50's.
Depending on temp/ humidity, the mortality rate can vary on different bugs and growth stages.
40-60% mortality when used alone on some bugs isn't unusual in field studies. 80%+ isn't unusual either, so it varies.
Using it in conjuction with other agents , like azadiractin, then mixing it with pyrethrin the next time, or Grandevo and Venerate rotations will get the mortality rates way up there. They can't recover from one, when another one hits them.
Even spraying neem one week, B bassiana the next works well, that's effective.
Prefer the powder, longer shelf life & the kaolin clay it's mixed with has it's own benefits. That's the residue you probably saw.