There are a lot of articles that say that the active ingredient in Garden Tech Daconil Fungicide Concentrate, Chlorothalonil, is safe to be used on orchids. Since the product itself is not labeled for them, the only rate we can give is for ornamentals which is 2 1/4 tsp - 3 tbs per gallon.
We would recommend contacting a local orchid specialist/nursery or the Master Gardener with your County Extension Office for their recommendations.
Garden Tech Daconil Fungicide Concentrate is labeled to treat rust on ornamental flowers. Per the label, to control disease already present, apply this product on a 7 day schedule until disease pressure is eliminated. Then continue spraying on a 14 day schedule to prevent the disease from reoccurring. To prevent Rust Leaf Spot diseases, Anthracnose and Scab, begin applications at the first sign of spring budding. Please see the label for full application instructions.
