Q.I am not sure if this is Begonia Blight or not. Is there anything I can do. This is a potted begonia.
I grow many begonias. This one is a Rhizomatous and is a fairly new purchase. I have had this problem on other begonias (even discarded one recently) but this new plant has not been near the other affected ones. I have also been careful to sanitize my snips so as not to spread the disease.
Certified GKH Gardening Expert
It looks more like bacterial leaf spot. These can be confused with fungal leaf spot so it's best to get a diagnosis from a plant disease clinic. Your area Cooperative Extension Service should have one. Rhizomatous begonias are sensitive to water on the leaves and should be watered from below. Here is more information on management:
https://extension.psu.edu/begonia-diseases
https://www.gardeningknowhow.com/ornamental/flowers/begonia/begonia-leaves.htm
https://www.gardeningknowhow.com/ornamental/flowers/begonia/begonias.htm