Recent advances in cultural management of diseases of greenhouse crops

Disease management in greenhouse crops offers a particularly difficult challenge because the environmental conditions for optimum crop production are often also conducive to disease development. With the current restrictions in pesticide usage in greenhouses, cultural and biological methods are often the only alternatives for disease management. In the last few years, several new technologies which offer more natural ways of controlling pathogens have been studied and proposed for commercial use. Canadian scientists have been involved directly in the development and/or the advancement of a considerable number of pest management technologies with potential application in greenhouses, some of which are described here. These include the use of natural products such as soluble silicon and plant extracts for disease control on long English cucumber; the use and development of biological control agents, such as Sporothrix flocculosa, Tilletiopsis spp., and Ampelomyces quisqualis, to control powdery mildews of greenhouse crops; and the sterilization of hydroponic solutions using different physical methods to prevent the introduction and spread of root and crown pathogens in closed recirculating hydroponic systems. The effectiveness of these different management practices, their possible mode of action, and their commercial potential are presented.