also neem and sulfur are not very compatible with each other. Application sulfur should be separated by one month before or after any oil. When used together, they burn plants. Sulfur is a preventive as well as a very old insecticide. Neem is also good for controlling some insects and as a preventive but does not work well as a control. In reality very few topical fungicides work well as cure. Both are not benign and are toxic to bees and other animals as well as being an eye and skin irritant so read and follow label directions, always. The label will tell you how to apply and how often.
"... But do not use sulfur if you have applied an oil spray within the last month. Sulfur can injure plants if used when
temperatures exceed 80 degrees Fahrenheit."
https://www.bbg.org/gardening/article/l ... t_diseases
https://www.biconet.com/botanicals/infos ... lLabel.pdf
Happy gardening in Hawaii. Gardens are where people grow.