Copper oxychloride is the more soluble of the fixed coppers and should be used with great caution. Alkaline coppers such as bordeaux can reduce the efficacy of other fungicides and insecticides. Some fungicides such as fosetyl-Al are acidic and if applied in association with copper can result in severe phytotoxicity. Always apply copper products to a few plants and observe results until you have gained experience. For greenhouse or other enclosed structures only.
Resistance is a threat.