Hello @sguyader
I’m also a plant pathologist, so if you can share photos of diseased leaves, maybe as a Play Raw, I’ll be on it!
It would be fun indeed but I do fear we are going to “scare” the photographers of this forum with our pictures of very diseased leaves 
Joking aside, here is a picture of a bacterium, on Pepper leaves, quite common in Northern Italy, that is Xanthomonas vesicatoria (leaves + gyca and csga petri dishes with the bacterium at 2 days of growth) :
Here is the NEF raw file in case you are interested: