Captan is hard on pollinators. Immunox is somewhat better but still not good. My advice at this point would be wait til petal fall and then spray a mixture of Captan and Immunox. Make sure the spray water is acidic before adding the Captan as it is destroyed by basic water.
Here is a link to agriculture chemicals and their toxicity to pollinators. For Immunox you will have to use the chemical name( it is on the label of your container) to search for it since the brand name Immunox is only used for retail buyers not commercial growers.
https://ipm.ucanr.edu/bee-precaution-pesticide-ratings/
Also have a look at this post and the link included in the post. It will help you understand the disease better and plan when and what to spray.