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 produ ction are often also conducive to disease development. With the curren t restrictions in pesticide usage in greenhouses, cultural and biologi cal 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 comm ercial use. Canadian scientists have been involved directly in the dev elopment and/or the advancement of a considerable number of pest manag ement technologies with potential application in greenhouses, some of which are described here. These include the use of natural products su ch as soluble silicon and plant extracts for disease control on long E nglish cucumber; the use and development of biological control agents, such as Sporothrix flocculosa, Tilletiopsis spp., and Ampelomyces qui squalis, to control powdery mildews of greenhouse crops; and the steri lization of hydroponic solutions using different physical methods to p revent the introduction and spread of root and crown pathogens in clos ed recirculating hydroponic systems. The effectiveness of these differ ent management practices, their possible mode of action, and their com mercial potential are presented.