Read the product label and follow the instructions precisely. Make sure the plant you will be treating is listed on the label. Apply the control correctly following all label instructions. To be effective, fungicidal sprays must be applied properly. They work by creating a barrier that pathogens cannot penetrate.
Good coverage is important.
Give special attention to the underside of leaves, especially lower leaves. The barrier's effectiveness is affected by how well the spray spreads and sticks. If you are not sure about coverage, observe the pattern spray deposits. Apply at the recommended time. In many cases, fungicides are a protectant and must be applied just before the pathogen is able to infect the plant.