Leaf Doctor is a free iPhone application available for download at the iTunes store for quantitative assessment of disease severity.
Leaf Doctor Version 1.1 is now available for download from iTunes and is compatible with iOS 11 or above.
Further information on Leaf Doctor is available at the following link: https://sites.google.com/a/hawaii.edu/leafdoctor/
Information on Leaf Doctor is also available in the paper published in the journal, Plant Disease.
An Android version of Leaf Doctor is now available for download from the Google Play Store.