Leaf Doctor is an Android application developed by Sarah Jane Pethybridge. It falls under the category of Education & Reference. Leaf Doctor is a powerful tool that performs quantitative assessments for plant diseases on various plant organs, particularly leaves.

The main feature of Leaf Doctor is its ability to analyze photographs of diseased plant organs and calculate the percentage of diseased tissue. Users can either collect new photographs or submit existing ones for analysis. The app employs an algorithm that utilizes user-specified values for up to eight colors of healthy tissues in the photograph. Each pixel's color is then evaluated for its distance from the healthy colors and assigned a status of either healthy or diseased.

To ensure accurate representation of diseased tissues, users can slide a threshold bar until they are satisfied. The assessment data and photographs can be easily sent to recipients via email. The app also provides detailed instructions on how to use its features.

Leaf Doctor was produced by Cornell University and the University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources. It is a valuable tool for plant enthusiasts, researchers, and professionals in the field of agriculture.