Isolating Globisporangium ultimum (Pythium ultimum) in Vitro to Study Biofungicide Treatments on Amaranthus tricolor Hydroponic Microgreens
Growing microgreens hydroponically is a cleaner and more efficient process. However, many hydroponic systems are afflicted with recurring cases of root rot, commonly caused by Globisporangium ultimum (formerly Pythium ultimum), which can destroy crops within a couple of days. Despite this, there are minimal scientific resources addressing the issue. Thus, this study explores techniques that can be performed in the greenhouse for isolating G. ultimum from infected microgreen Amaranthus tricolor. Infection of A. tricolor was induced by placing frozen samples taken from previous infections into the hydroponic reservoir. Symptoms showed after the third crop cycle, roughly three weeks after the initial infection of the water. Sanitization was achieved in the greenhouse with solutions of 16% sodium hypochlorite (Clorox bleach) and then 70% propanol alcohol. Isolation methods included either collecting spores from mycelium growth on dying plants or collecting an infected root, then placing them onto potato dextrose, V8, or water agar. After multiple experimental trials, results indicated that G. ultimum growth was most successfully isolated from placing an infected A. tricolor root on potato dextrose agar when incubated at around 26 degrees Celsius for four days in the dark. These efforts help inform future trials to study the long-term storage of G. ultimum and to explore the efficacy of bio fungicide treatments, such as Orca (rights reserved) Liquid Mycorrhizae, to prevent root rot infections in hydroponic microgreens.
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