I do like this idea, but I don’t think it’s feasible. For one thing, I agree that
I personally don’t mind adding host plant observations, but no one should be required to. Also, it’s a multi-step process to add links to other observations. If you submit both observations at the same time, you have to save them, then go to each one’s “Edit” page and add Notes with a link to the other. It’s tedious if you have to do it multiple times, so it definitely doesn’t make sense for anyone who uploads a lot of plant parasite observations.