Articles
AN INTEGRATED CONTROL MEASURE FOR PYTHIUM ROOT ROT OF HYDROPONICALLY GROWN GREENHOUSE CUCUMBERS
Article number
644_76
Pages
571 – 574
Language
English
Abstract
Greenhouse cucumber production is valued at about 90 million dollars annually in southwestern Ontario.
The cucumbers are grown hydroponically in a rockwool or NFT (nutrient film technique) system where their root systems are partially or fully submerged in the nutrient solution.
Such growing systems are conducive not only to the development of Pythium root rot but also to the spread of the disease.
In the past several years, an integrated control measure was successfully devised by integrating pH, bioagent, and ultra-violet (UV) light to control Pythium root rot of tomato.
This paper reports the successful application of the same measures in the control of Pythium root rot of cucumber which is more susceptible than tomato.
Although the degree of control was less than that in tomato, by replacing the susceptible cultivar Flamingo with a less susceptible Bodega, the integrated measure can reduce Pythium root rot by about 80%. This integrated control consists of a) before transplanting, the UV system is connected to sterilize the recirculating solution using 80 to 100 mJ cm-2; b) after transplanting, the nutrient solution should be delivered at a pH 5.0 regime for about five weeks followed by adjusting the pH to a 5.8 to 6.2 regime for one week; and c) bacterial bioagent, such as Pseudomonas is introduced into the root zone at 100 ml plant-1 at 108 bacteria ml-1.
The cucumbers are grown hydroponically in a rockwool or NFT (nutrient film technique) system where their root systems are partially or fully submerged in the nutrient solution.
Such growing systems are conducive not only to the development of Pythium root rot but also to the spread of the disease.
In the past several years, an integrated control measure was successfully devised by integrating pH, bioagent, and ultra-violet (UV) light to control Pythium root rot of tomato.
This paper reports the successful application of the same measures in the control of Pythium root rot of cucumber which is more susceptible than tomato.
Although the degree of control was less than that in tomato, by replacing the susceptible cultivar Flamingo with a less susceptible Bodega, the integrated measure can reduce Pythium root rot by about 80%. This integrated control consists of a) before transplanting, the UV system is connected to sterilize the recirculating solution using 80 to 100 mJ cm-2; b) after transplanting, the nutrient solution should be delivered at a pH 5.0 regime for about five weeks followed by adjusting the pH to a 5.8 to 6.2 regime for one week; and c) bacterial bioagent, such as Pseudomonas is introduced into the root zone at 100 ml plant-1 at 108 bacteria ml-1.
Authors
J.C. Tu
Keywords
ultraviolet irradiation, medium acidification, Pseudomonas bioagent
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