Model of B. cinerea and practical use
Sensors: Leaf Wetness, Temperature, relative Humidity
In FieldClimate.com we use the following correlation between leaf wetness duration and temperature to model the disease.
Botrytis cinerea is a fakultative parasite. It growths on dead plant material too. Because of this fact it is always present in vineyards and orchards. Botrytis cinerea is related to moist climate. For infection it needs very high relative humidity or the presence of free water (sensor: leaf wetness, relative humidtiy). The fungus is unable to infect healthy adult plant material by spores. Infection takes place on young shoots of the vine during longer wet periods or an shoots damaged by hail storms.
The FieldClimate Botrytis Risk Model results in a risk value of 0 to 100%. This value indicates the pressure of B. cinerea at the time. If we have a value of 100% it means that there has been several times a wetness period long enough to infect the susceptible tissue (we calculate so called "wet points" (array between leaf wetness, temperature with a maximum of initially 38400 points (beginning of season, which displays 30% risk). After this period each wet period with about 4000 wet points (array) increase the risk with 10% or on the other side each dry periode reduce the risk by 1/5 of the former value.
An application against B. cinerea is depending on the fuit and the production target.