You got me interested. All I read about Ento leaf spot is that if affects plants in Rose family including apple and pear. None mentioned that it affects cherry.

Are you sure you don't have bacterial leaf spot on cherry? It's a common disease for cherry. You should Google pictures of the bacterial leaf spot on cherry and compare. Some look like yours, too.

Your cherry leaves look quite different from cherry leaves on all my trees. Yours is wide with round top. Mine is narrow with pointed tip.

Anyway, I don't know the fungicide you use but fungicide like myclobutanil (brandname like Immunox) or chlorothalonil (Daconil) is recommended for both Ento leaf spot and bacterial leaf spot.

It could be that. I bought Green Earth Fungicide today. It's a Canadian made product, supposedly eco-friendly. The active ingredient is sulphur. Do you think it might work? Or those ingredients you mentioned are better?

I went to many different stores, and this was the only product they were selling as a fungicide.

Sulfur is listed for cherry leaf spot, so it's appropriate. I use it for pear blister mites.

I suggested you mix sticker such as Bonide Turbo sticker/spreader, to help sulphur stick to the leaves longer.

I hope Canada allows Turbo sticker/spreader to be sold.

It seems like the fungicide I mentioned previously would be more effective but if it's not sold where you are, your choice would be sulfur.

Looks to me like Cherry Leaf Spot aka Blumeriella jaapii. It should respond to captan or a similar fungicide but captan is not organic. You might read the attached article.

Here is a link that might be useful: Cherry Leaf Spot