Identification of greenhouse characteristics which affect the incidence ofSclerotinia sclerotiorum (Lib.) de bary in pepper crops in a Mediterraneanclimate

The effect of the main construction factors and design features of greenhou ses on the incidence of 'white rot' disease, caused by Sclerotinia scleroti orum (Lib.) de Bary, was studied in peppers grown under plastic-roofed gree nhouses typical of Almeria (SE Spain). At the height of the pepper-growing season in the province, fifty greenhouses were repeatedly sampled. Incidenc e of the disease was measured and the different construction features of th e greenhouses were evaluated: types of roof cover, colour and age of the pl astic cover, dimensions (ground plan, surface area, average height), estima ted ventilation capacity and the presence of netting on the sides of the gr eenhouses (laterals). Statistical analyses were undertaken to see if the ch oice of various design options for each factor had any significant influenc e on the incidence of the disease. To achieve this single factor ANOVA was undertaken. The incidence of this disease was significantly affected (p < 0 .05) by the following greenhouse characteristics: ground plan, surface area , mean height, colour of the plastic cover, estimated ventilation and use o f lateral netting.