If you want to go with stuff you can find locally. Any liquid copper spray would help. Like Liqui-cop (The best of the liquid coppers) and Bonides sticker would do. You should be able to find these at any garden center. You will need a pump sprayer.
Make sure to follow label directions exactly, as I said chance of injury to leaves if you use too much. Kocide is Copper Hydroxide and the 2tb dose was as a dormant spray only after leaves fall. Not what you need now, the liquid coppers might even be better for this situation and you can still use them as dormant sprays. I think Kocide is not allowed in CA anyway.
Captan is another option you should find locally and probably works better or just as well as copper. One thing with this, you must use neutral water to mix, buy a gallon of distilled water or use rainwater. Tap water will neutralize the Captan, not worth even putting on.
For anybody growing fruit trees try to find Nufilm 17 sticker to use with pesticides. it is made with pinene which is an extract of pine trees. Kinda like a clear pine tar. Provides UV protection too, thus pesticides don't break down on tree as fast. Look at this photos these are sweet cherry flower buds after 12 hours of straight rain. Look at the stems see the copper? I applied 2 days earlier. The rain didn't touch it!
