Disease risk from the weather, with the source attached
FairGrow works out for each field whether the weather gives a disease or pest a chance. Every signal follows a published model, and you can see which one.
A fungus waits for wet leaves
A fungus only infects when the leaves stay wet long enough at the right temperature. FairGrow counts those hours for your field: the past 48 and the next 72. If the total passes the model’s threshold, the signal turns orange or red.
- With the values attached: how many wet hours, at what temperature.
- With the source attached: the publication the threshold comes from.
- Per field and per crop, not one signal for the whole region.
How the model counts
Twelve disease models, per crop
Each model comes from the scientific literature and was built for one disease on one crop. If a disease has no model of its own, FairGrow falls back on Magarey’s general infection model, with parameters for about 50 pathogens. The signal says so when that happens.
| Crop | Disease | Model and source |
|---|---|---|
| Potato, tomato | Late blight | Hutton (2017), Smith (1956), Wallin (1962) |
| Potato | Early blight | P-days, Sands et al. (1979) |
| Tomato | Early blight | TOMCAST, Madden et al. (1978) |
| Apple | Scab | Revised Mills table, MacHardy & Gadoury (1989) |
| Sugar beet | Cercospora leaf spot | Wolf & Verreet (2005) |
| Grape | Downy mildew | 3-10 rule (Baldacci 1947), spore model Brischetto et al. (2021) |
| Strawberry | Gray mold, anthracnose fruit rot | Bulger et al. (1987), Wilson et al. (1990) |
| Other crops | Including septoria, rusts and monilinia | General infection model, Magarey et al. (2005) |
Insects follow the warmth
Codling moth, carrot fly and cabbage root fly emerge once enough warmth has built up. FairGrow counts the degree days from the start of the season and shows when the flight begins. That way you set traps and checks at the right moment.
- Codling moth (apple, pear): first flight at 151 degree days above 10 °C, counted from January 1.
- Carrot fly: 260 degree days above 5 °C, counted from March 1.
- Cabbage root fly: 210 degree days above 4 °C, counted from March 1.
Warmth adds up
Where you see it
A card with the signal per field. On orange or red it shows how many products are authorized in your country for this crop against this disease, with a link to the product check.
Per field the signal, the underlying values, the source and a 14-day strip. With the seen or not seen buttons you tell us whether it was right.
On orange or red a message if you want one, at most one per field per day.
What it is not
- Not a spray recommendation. It is a risk signal. The label and your own observation come first.
- Leaf wetness is calculated, not measured. FairGrow estimates it from humidity and rain.
- Tested elsewhere. Most models come from the US, the UK, Italy and Norway. Their thresholds were tested there, not on your farm. That is why your seen or not seen reports count.
Do you grow grapes? How we adopted and calibrated the spore model for downy mildew is explained on the page about the spore model.
Short answers
Do I need a leaf wetness sensor?
No. The models use the hourly forecast and the weather history for your field. If there is a temperature and humidity sensor within 250 meters, FairGrow uses those readings as well.
Which weather do the models use?
The hourly forecast from Open-Meteo and the ERA5 reanalysis for the past days. How reliable such a forecast is, you can read on the page about the verified forecast.
Will I get an alert?
If you want one, by email or via Telegram. Only on orange or red, and at most once per field per day.
Is this a spray recommendation?
No. The signal says the weather made an infection possible. Whether you act, and with which product, is your decision. Which products are authorized you can see under crop protection.