The BOTRYTIS ALERT is a recently developed webservice, a data program on internet, that warns for risks on botrytis infection in tomato. The webservice can be bought by tomato growers and has been developed within the Healthy Greenhouse (‘Gezonde Kas’) project in which Wageningen UR Greenhouse Horticulture and 32 other institutes and companies participated.
The calculation rules are based on existing relationships between dynamics of the botrytis fungus and climate variables (temperature, humidity, radiation). Especially when a humid condition prolonges for a longer time period, and hardly being interrupted by dry episodes, a risk will be predicted.
Temperature and humidity
For each point in a sensor grid that records temperature and humidity, the webservice calculates the risk separately. Risk above a certain threshold is indicated by a red backgroud around the grid point (see figure). In this way cold and humid locations in the greenhouse and the associated botrytis risks become apparent. The sensor grid is similar to the one used for the so-called ‘Wandelende Meetbox’ (roaming climate measuring box).
Use of spore collectors
The risk increases at a high spore pressure. Thus, for the BOTRYTIS ALERT the use of spore collectors is recommended. Yet, spore pressure is also simulated and depends on the time course of the measured vapour pressure deficit. For this approach an observed relationship, depending on spore production on old, humid and decaying leaves is being used.
The prediction of Botrytis infections to a certain extend remains uncertain. Especially because the most frequent form, stem botrytis, also depends onthe way of leaf picking, the hygiene level in the greenhouse and the resistance of the plant. These aspects are considered in the Healthy Greenhouse system, and the webservice can be connected to that system for an additional price. The webservice can operate on every software platform as long as internet is available.