Kyle writes
I would like to mix this with Bonide Liquid Copper Fungicide or use both in an alternating schedule to treat a severe outbreak of rust and leaf black spot in an ornamental flower bed. I would also be open to using a synthetic fungicide if it would be more effective.
Per the label for Bonide Neem Oil, it can be mixed with a dormant or delayed dormant spray to control various types of fungus. We would recommend mixing a small amount first to ensure there is no clumping with the two products. A better option for what you are wanting to accomplish is Fertilome Triple Action with Neem Oil. It is an insecticide, fungicide and miticide all in one. It will kill the rust and leaf black spot and can be used on ornamentals.
Answer last updated on: 06/25/2015