Methodology: Plant Sickness Identifier

Where our information comes from

Every plant-problem guide is written against public horticultural references: university extension services (UC IPM, NC State, Penn State, Wisconsin, Colorado State), the Royal Horticultural Society, and national plant-health bodies. Each guide lists the exact pages it relies on, and a claim with no supporting page is dropped rather than kept on trust. The review ledger for every guide lives in the repository as THREATS-REVIEW.md.

How we use AI

AI helps draft and organize the guides and powers the diagnosis inside the app. On this site, every factual claim about a pest or disease, its hosts, its season and its treatment must be traceable to a named source and is checked before a page becomes indexable.

What a diagnosis means

A result from the app is a first read of what a photo shows: the plant, the visible symptom and its most likely cause, with a match confidence that says how cleanly the photo read. It is not a laboratory test, and a cause that lives in the roots or inside a stem can be invisible to a leaf photo. Treatment plans start with cultural steps and name chemical controls only by type; the product label and your local extension service decide any pesticide or fungicide use.

Corrections

We want to get this right. If you spot an error, tell us and we'll review it against the sources and update the guide.

How the guides are built

Each problem is described the way a grower meets it. The signs come first, in the order a person tends to notice them, because a diagnosis is only useful if it starts from what you can actually see. Then the lookalikes: for every problem, the one or two others it is most often mistaken for and the single detail that separates them, since treating the wrong problem is how a mild case becomes a bad one.

Treatment steps run from the least intervention to the most. Pruning, hand-removal, a change in watering or airflow, and physical barriers come before any spray, and sprays are named only by class, such as insecticidal soap, horticultural oil or a fungicide labelled for the disease. This site never states rates, dilutions or product brands. Those belong to the label and to local regulation, which differ by country and change over time.

Two things are deliberately left out. Guides do not cover diseases that must legally be reported to a plant-health authority, because those need an official diagnosis rather than a phone photo, and they do not recommend home remedies that lack a published basis.

Guides are re-checked against their sources when a source page changes and at least once a year, and the date shown on each page is the last time that check ran.