Dan from Akron Ohio writes
Chlorothalonil 720 SFT Fungicide is intended for larger scale applications at the rate of 5.5 pints (88 fl oz)/per acre. This would break down to 2 fl oz per 1000 sq ft in a sufficient water volume for foliar applications. For smaller applications, Garden Tech Daconil Fungicide would be an easier rate per applciation. For Rhizosphaera Needlecast, the rate per the product label is 3 tbsp per gallon of water.
Keep in mind, there is a risk of bleaching Blue Spruce with chlorothalonil for diseases. For best effectiveness, fungicides should be applied when the emerging needles are half elongated (1/2 to 2 inches in length).
Answer last updated on: 08/19/2021
