Inactivation of plant pathogens in irrigation water runoff using a novel UV disinfection system
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Untreated recycled irrigation water has been shown to introduce and spread plant pathogens such as Pythium and Phytophthora in commercial nurseries. Nevertheless, few nurseries currently treat their recycled irrigation water. Instead, nurseries use prophylactic pesticides to control the spread of plant pathogens, which increases costs and promotes the growth of resistant pathogens. Of interest to California is the spread of Phytopthora ramorum, causal agent of Sudden Oak Death (SOD), responsible for the death of tens of thousands of trees in California and Oregon. This study investigated the use of a novel UV disinfection system to inactivate P. ramorum and other microbial contaminants at the National Ornamental Research Site at the Dominican University of California (NORS-DUC). In this system, the UV lamps do not come in contact with the water and hence remain free of the ‘lamp fouling’ problem. Tests on waters having the same characteristics as run-off from commercial nurseries showed a minimum of 3.7 log removal of bacterial species, 91.7% reduction of fungal counts, and 100% inactivation of the P. ramorum in the effluent. Treating the run-off from plant nurseries limits the spread of plant pathogens and enables the onsite re-use of the run-off.
KeywordsPhytopthora ramorum UV disinfection Vortex reactor Irrigation run-off Nursery plants
This work was funded by the Sustainability Training and Research Program (SRTP), University of California – Davis, and by Diamond Developers, The Sustainable City - Dubai. We thank Dr. Suprya Shama (NORS-DUC) for technical assistance in the NORS-DUC lab.
Compliance with ethical standards
The authors declare that this manuscript reports on original research that has not been published elsewhere. All the authors have read and approved this manuscript. All authors also declare that the data have not been manipulated. This manuscript does not contain any experiments with human participants or with animals.
Conflict of interest
The authors declare that they have no actual or potential conflict of interest.
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