How long should I allow pressure-treated plywood to dry before applying non-skid strips?
Have you read the instructions? I'd start there, especially since you haven't told us what product we're talking about.

In reality the plywood will take weeks or longer to truly dry out, and depends heavily on your weather and sun exposure. The answer to your question partly depends on the size and shape of the tape. If it's composed of narrow strips, I'd wait at least a few days (in the sun) or a week (in the shade) so that the surface is noticeably dry. If it looks dark and damp or feels cool, your adhesive probably won't bond well. 

If the tape is wide or a full sheet, give the wood much longer to dry out. You'll effectively seal in the water, and it may collect beneath the tape and cause it to release.