b'A New Disease Lurking in Potato StoragesA new potato disease called rubbery rot is popping up in potato storages across North America.BY: ASHLEY ROBINSONKASIA DUELLMAN IS used to growersThe rubbery rot was actually detected bringing in diseased tubers from potatoalong with several other diseases in the storages to her University of Idaho (U ofsame storage area. But rubbery rot was I) lab and asking whats wrong with them.detected alone in some of those tubers But she found herself stumped one day inby itself causing an issue independent November 2020. from some of the other standard storage The tubers had been stored for a monthdiseases, Willbur, an assistant professor and now had a rubbery texture along withwith Michigan State, says in a phone expelling a sour milk odour. She slicedinterview.them open and started examination. OnThe rubbery rot incidence was first look it seemed the tuber had pink rot,relatively low at less than one per cent. but as it sat sliced apart it didnt turn theSince the initial discovery in 2018, Willbur salmon pink colour. says theyve found it in storages from Duellman shipped the mysteriousthree additional counties in the Lower spuds over to her colleague JamesPeninsula.Woodhall, the U of Is plant pathologistThe storage disease has also come in Parma, Idaho. Woodhall and hisacross the desk of North Dakota State team performed molecular assays andJamie Willbur, assistant professor withUniversity Plant Pathology Professor isolations on the tubers recovering theMichigan State Gary Secor. In 2022, it was found in Geotrichum candidum pathogen. several samples from some Midwestern They conducted what we callpotato growing states at a relatively low pathogenicity tests to confirm theincidence, he states in an email. It has so pathogenicity of Geotrichum candidumfar only been noted in various processing because rubbery rot had never beenpotato varieties.documented in Idaho. We knew it couldWhile rubbery rot may be new to the infect potatoes and cause this diseaseNorth American potato industry, the called rubbery rot, but it never had beenpathogen that causes it isnt new to the documented here before, Duellman, thecontinent. The Geotrichum candidum U of I seed potato specialist, explains in apathogen is a mold that is yeast like. It phone interview. behaves as yeast and is used in food Pathogenicity tests were conducted,processing with some strains of it used as and it was confirmed that Woodhallsa rind on cheese.team could duplicate the symptoms fromGeotrichum candidum is found in the tests, meaning Idaho officially had itssoils around the world and the fungus first case of rubbery rot. is part of the human microbiome. Well, The Pacific Northwest state isnt theit causes rubbery rot on spuds, and can only location where rubbery rot has beenalso cause storage diseases on fruit. Sour found recently. In 2018 Jamie Willbursrot on strawberries, peaches, nectarines, potato and sugar beet pathology lab at theGary Secor, plant pathology professor atand melons, is caused by Geotrichum North Dakota State UniversityMichigan State University received somecandidum.tubers from a potato storage that hadThe fungus causes the fruits and disease in it. tubers that it infects to kind of smell like 14SPUDSMART.COM Winter 2023'