Right. Which is why I was surprised to see new yellowing on leaves I had sprayed! I did 1.5 T baking soda, 1/2 T oil, a few drops dish soap, and 1/2 gallon water.

So you would think this is fungus and not other damage?

Yellowing lower leaves? There are other potential causes, such as nitrogen deficiency. However pics?

I attempted to put a photo there! So sorry. It must not have loaded and I didn’t notice. I have used Miracle Gro once so a N deficiency would surprise me (but I am still a beginner in many ways!)

Baking soda is a remedy for the common disease Powdery Mildew, but not anything else to my knowledge. Powdery mildew is very unique as far as fungal disorders go and is amenable to control by baking soda....or even a rinse with water from the hose.

Not true for early blight or any other fungus disease.

Looks like bacterial leaf spot to me.

I would dispose the infected leaves in the trash.