Leaf Doctor

Name: Leaf Doctor
Author: University of Hawaii

University of Hawaii

VALIDATED

Initial evidence from research studies

For:Researchers & AcademicsGeneral Public & EnthusiastsIndustry Professionals

Free

Download on the App Store

App Summary

Leaf Doctor is a mobile application designed for researchers and agriculturists to quantify the severity of plant diseases by analyzing smartphone images of leaves. The associated research demonstrated the app's high accuracy (R2 ≥ 0.79) and precision when compared to a standard image analysis tool across six different plant diseases. The authors conclude that Leaf Doctor provides a low-cost, easy-to-use, and portable tool for rapidly assessing plant disease in the field.

App Screenshots

Detailed Description

Functionality & Mechanism Developed by the University of Hawaii at Manoa, Leaf Doctor facilitates quantitative assessment of plant disease severity from digital images. The system processes user-submitted photographs of plant organs, such as leaves. The interface captures input as the operator selects up to eight colors representing healthy tissue. A threshold algorithm then isolates symptomatic areas, which are visually confirmed before the system calculates the percentage of diseased tissue. Resulting data and annotated images can be exported via email.

Evidence & Research Context

A validation study demonstrated high accuracy (R² ≥ 0.79) for disease severity estimation when compared against the discipline-standard software, Assess.
The tool exhibited robust precision across six different plant diseases, with low coefficients of variation (0.51% to 14.1%) for repeated measurements of the same image.
The associated research noted a significant negative relationship between measurement variation and mean disease severity, indicating greater precision on more severely diseased samples.
The protocol also highlighted operational advantages, including reduced image processing time and the capacity to generate standard area diagrams for research.

Intended Use & Scope This application is designed for plant pathologists, agronomists, researchers, and educators requiring objective measurements of disease severity. Its primary utility is the quantification of visually present symptoms, not disease diagnosis or identification. Accurate operation depends on the user's ability to correctly distinguish healthy from diseased tissue. Results are intended to supplement expert pathological assessment.

Studies & Publications

1 publication

Peer-reviewed research associated with this app.

Validation Study

Leaf Doctor: A New Portable Application for Quantifying Plant Disease Severity

Pethybridge et al. (2015) · Plant Disease

App measurements accurately matched the reference standard with high precision across multiple plant diseases.

An interactive, iterative smartphone application was used on color images to distinguish diseased from healthy plant tissues and calculate percentage of disease severity. The user touches the application's display screen to select up to eight different colors that represent healthy tissues. The user then moves a threshold slider until only the symptomatic tissues have been transformed into a blue hue. The pixelated image is then analyzed to calculate the disease percentage. This study reports the accuracy, precision, and robustness of Leaf Doctor using six different diseases with typical lesions of varying severity. Estimates of disease severity from Leaf Doctor were highly accurate (R2 ≥ 0.79; Cb ≥ 0.959) compared with estimates obtained from the discipline-standard, Assess. Precision was operationally defined as the ability of a rater to use Leaf Doctor and repeatedly obtain similar percentages of disease severity for the same image. Coefficients of variation were low (0.51 to 14.1%) across all disease datasets but a significant negative relationship was found between the coefficient of variation of estimates and mean disease severity. Other advantages of Leaf Doctor included comparatively less time for image processing, low cost, ease of use, ability to send results by e-mail, and the ability to create realistic standard area diagrams. Leaf Doctor is compatible with iPhone, iPad, and iPod touch and is optimized for iPhone 5. It is available as a free download at the iTunes Store.

In the Media

Leaf doctor makes the rounds

Cornell's Sarah Pethybridge and the University of Hawaii's Scot Nelson developed Leaf Doctor to quantify disease severity in plants, using photo analysis technology that distinguishes diseased areas from healthy tissue. "This is a reliable way to get actual percentages of disease severity, by comparing pixels covered by disease and pixels covered by healthy tissue," Pethybridge said. The free app launched on iOS in 2015 and recently became available for Android users through Google Play.

CornellRead article

The leaf doctor is in

University of HawaiÊ»i plant pathologist Scot Nelson developed Leaf Doctor to help researchers accurately quantify plant disease for epidemiological studies, using smartphone photography and interactive touch-screen technology. Nelson notes that while existing PC-based systems cost $795 and are "difficult to use, not interactive and not particularly accurate," his free iOS app "is accurate to within a percentage point." The app allows users to photograph plant tissue, identify healthy areas by touching the screen, and automatically calculate diseased tissue as a percentage of total leaf area.

HawaiiRead article

Plant pathologist creates new plant disease assessment app

CTAHR plant pathologist Scot Nelson developed Leaf Doctor to provide more accurate disease severity assessment for researchers and plant professionals, replacing decades-old methods that rely on comparing plants to printed standard area diagrams. Nelson anticipates that "for many of those who will use the Leaf Doctor, it is likely to be a professional game-changer" in plant epidemiology work. The specialized app targets researchers studying disease resistance and breeders developing new plant varieties, unlike Nelson's broader Plant Doctor app used globally.

HawaiiRead article