Here is our page on Growing Cucumbers: 
https://extension.umd.edu/resource/growing-cucumbers-home-garden which includes the common problems this crop has here in Maryland.
While they can get some leaf spot diseases, angular leaf spot is not common and our vegetable specialist thinks that the lesions are more consistent with Downy Mildew. See here:
https://extension.umd.edu/resource/downy-mildew-vegetables

We would not recommend any sprays at this point. Fungicides are not curative, only preventative.
Chlorothalonil would've been effective to protect new tissues if it had been applied earlier in the season. Neem would not be effective, and is not good for beneficial insects.  
We are not sure about Triforine.


Christine