biofilm
Biofilms on channel surfaces are often not able to be seen , however may become visible if the surface has become colonized by algae .
Use of disinfection agents at high concentrations provide good control of biofilms in systems shut down for cleaning . These compounds are far less effective when run at lower concentrations when plants are present and run the risk of root damage . Some research studies have indicated that UV ( ultra violet irradiation ) and ozone disinfection of the nutrient solution can reduce biofilm growth , but not completely eliminate it . These methods should be used with caution as they can affect the availability of certain nutrient ions in the solution . In the future , we can expect to see some new and innovative treatments for the root disease pathogens harbored in biofilms . These innovations are likely to center around inoculation with biosurfacant producing and other suppressant microbes , rather than complete elimination of biofilms themselves . While the prospect of biofilms colonized with disease pathogens that continually reinfect a hydroponic system is frightening , in reality , most soilless systems harbor many beneficial populations of microbes which help suppress pathogens . Many large commercial hydroponic systems exist that have been in operation for years with no regular removal of biofilms or any thorough cleaning of irrigation lines and system surfaces , and root disease is not encountered .
However , other growers both large and small have encountered frequent outbreaks of Pythium and other pathogens known to inhabit biofilms . If released into the nutrient solution , they carry the potential to cause disease — if conditions are inductive for development . In these cases , where a root rot disease outbreak has occurred , control and elimination of biofilms is an important step in the clean-up process to prevent reinfection .
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