The first two definitely seem like things that one could easily imagine a kit for: include primers for the species of interest, a bit of positive control, and p

The first two definitely seem like things that one could easily imagine a kit for: include primers for the species of interest, a bit of positive control, and perhaps even the Taq and other reagents you'd need. Then, the user could just collect their sample and run the PCR and a gel. The third might be a bit harder to make a commercial kit for while steering clear of patents. It's also not clear to me what kinds of samples you'd be able to test. An ear of fresh corn would probably work, but what about (un-)popped popcorn, or cornflakes, or corn starch? It would definitely take some experimentation. To make these kits really user friendly, ideally you could figure out some quick, easy way to determine the result of the PCR without running a gel, which require a relatively high voltage DC power supply and usually use Ethidium Bromide (a chemical that, depending on who you believe, is either nasty or really, really nasty) and UV light. I'm thinking maybe some kind of spectrophotometer-like setup, which are used in things like a NanoDrop, but I don't know how easy/economical it would be to build a DIY-level work-alike.