Any idea what causes these brown spots. I couldn't find any bugs on the leaves. thx
That's a fungus from here, one of the many leaf spots. Excellent year for it.
Thanks Dan. I'm wondering if I should use a contact spray fungicide or a systemic one? any suggestions? thx -j
Entomosporum mespii. Famous for getting on Photinia, it can get on other Rosaceous plants such as Amelanchier, Raphiolepis, and Pyrus. You may not see it every year on Pyrus, but you tend to see it more in years with wet springs. I would treat it like you would on Photinia, but it's not as serious on Pyrus. Any fallen leaves get rid of. New growth can be sprayed with mancozeb or chlorothalonil to protect it, otherwise, older growth should be sprayed with systemics such as propicanizole, tebucanazole, mycobutanil, or thiophanate=methyl. It's up to you to treat. If it's a large tree, I wouldn't worry about it. If it's a smaller tree, I'd consider it, especially if wetter weather seems to be more frequent.
Thank you for that great reply. -j