ANY wood you buy has the potential to be host to one or more destructive critters and/or their eggs.
</fueling the fear fire>. However, it's generally pretty rare.
When you think about how plywood is produced*, it's very unlikely that anything is going to live through the process. That means the only real way for anything to infest the plywood is to make the hop from "real" wood. This means that the plywood would end up being stacked near some solid lumber somewhere and the critters would need to decide to leave the "pure" luxury of solid lumber for the adhesive laden plywood. I'm no expert, but I'd guess that they're going to prefer solid lumber.
While this may not answer the question of how you can treat the plywood to prevent infestation, I believe that infestation is basically prevented during manufacturing.
No affiliation with the site, but it seems like a reasonably detailed explanation.