Epidemiology of Botrytis cinerea Diseases in Greenhouses

Botrytis cinerea causes problems in many greenhouse crops, such as tomato, cucumber, pepper, strawberry, sweet basil, rose, gerbera and most potted plants. In vegetables, it may infect fruits, leaves and stems. Stem infection resulting from growth through the petiole or from direct infection of wounds may cause plant death. In cut flowers, symptoms mostly occur during the post-harvest phase. In potted plants, disease is found both in greenhouses and post-harvest. In greenhouses, climatic conditions greatly influence epidemics caused by B. cinerea. The type of greenhouse covering influences sporulation by absorbing near-UV light, but may enhance disease by influencing the greenhouse climate. CO2 enrichment of the greenhouse air is not sufficient to reach effective levels. Sanitation is sometimes effective, especially when infected plant parts are removed from the crop, but does not suffice as a control method. No resistant cultivars exist yet, but cultivars show highly variable susceptibility. Wide plant spacing reduces grey mould. Cropping methods, such as de-leafing in vegetable crops, can reduce B. cinerea infection. The effect of nitrogen in the fertilizer is not consistent, but calcium enrichment of the plant tissue generally reduces susceptibility. Timing and method of the irrigation can also be used as a control measure. A combination of measures can be used to reduce the occurrence of B. cinerea-incited problems in greenhouse crops. Damage in vegetable crops occurs by reducing yield by loss of infected fruits, but mainly by plant death after stem infection. In ornamental crops, plants or flowers must be discarded when affected by Botrytis.