Here is a timelapse photo showing the speed of the bacterium/fungi growth over 3 days. It's faster than the leaves can grow.
As an experiment, I just sprayed one variable plant with olive oil to see if it can prevent it. I don't know the consequences other than people get sunburned faster with oil on their skin. My hope is that the oil suffocates the bacterium/fungi or somehow creates an environment that is not condusive for it's growth.
Other note: The issue seems to be isolated to the top part of the leaf, not the underside.
The attached photo isn't too large. If you'd like to see it in detail, let me know and I'll send the higher-resolution image. I tried including a link to the image on my server, but this forum doesn't allow links.
