CONTROL OF POWDERY MILDEW BY UV-C TREATMENTS IN COMMERCIAL STRAWBERRY PRODUCTION

Powdery mildew (Podosphaera aphanis) is one of the most common diseases in strawberry cultivation, and is mainly controlled by regular chemical interventions. In view of sustainable strawberry cultivation and the decrease of residues, the use of UV-c light can be a good alternative for controlling powdery mildew. Three different trials have been done investigating the possibilities of UV-c treatments on strawberry plants in commercial production systems, whether or not in combination with a biological preventive product (Vacciplant – laminarin). A high and a low dose were tested in the first trial in a commercial production. In a second trial on the regrowth of cut plants, different intervals and two doses were compared, and also the combination with Vacciplant was tested. The last trial in a commercial greenhouse production system compares the UV-c treatment in combination with Vacciplant with a chemical and an untreated control. Results show that UV-c treatments are able to reduce and even control powdery mildew, although there are some points of interest. It is important to use the right dose and treatment interval in order to prevent damage to the plants. Also the positioning of the lamps is important for reaching a satisfying result. Depending on the pressure, the use of chemical products can be avoided or reduced. In combination with Vacciplant, this technique is promising for sustainable powdery mildew control in commercial strawberry production.