Copper is one of the essential micro-nutrient elements for plants, but when in excess, is toxic to plants and other living organisms. Electrolytically generated copper and cupric sulphate are increasingly used by the greenhouse industry to control diseases and algae in hydroponic systems. However, there is little information regarding appropriate strategies for employing copper in greenhouse crop production. We investigated the physiological responses, growth and production of several ornamental crops (miniature rose, chrysanthemum and geranium) and greenhouse vegetable crops (pepper, cucumber, and tomato) with respect to Cu2+ concentration in the root zone. Tests were conducted using plants grown in nutrient solution, Promix and rockwool. Results showed that phytotoxic levels of Cu2+ were dependent on the crop species and growing substrate. Plants grown in nutrient solution exhibited symptoms of phytotoxicity at lower Cu2+ concentrations than those on the solid substrates. The ability of copper to control Pythium aphanidermatum and green algae was evaluated under both laboratory and greenhouse conditions. Copper was effective in suppressing green algae in nutrient solution, but did not control Pythium effectively. This presentation is a comprehensive summary of the research conducted over the last three years by our group on copper application in greenhouse systems.
Fusarium Wilts of Greenhouse Vegetable and Ornamental Crops
