How to effectively use copper fungicide in my heirloom tomato garden?
I'm facing a persistent issue with fungal diseases in my heirloom tomato plants, especially downy mildew. My garden is located in a humid area of the Midwest, and I've always favored open-pollinated heirloom varieties for their unique flavors. I've tried crop rotation and increasing air circulation, but it seems like the humidity is still a challenge. I've recently read about copper fungicide as a potential solution, but I'm unsure of the proper application methods and timing. Should I be concerned about phytotoxicity, especially on delicate heirloom leaves? I really want to protect my plants without compromising their health. Can anyone help with best practices for using copper fungicide effectively?