My research indicates the rust is specific to more than one Arisaema species. This is from the NARG newsletter of May/June, 2016 On the Lookout for Pests and Pathogens Maryanne Gryboski Two sizable colonies of Arisaema sikokianum showed signs of rust in my garden. I immediately began digging them out for trash pick-up and dashed off an email to the Ag Experiment Station. Here's what I learned: Jack-in-the-pulpit rust (Uromyces ari triphylli) is specific to that host plant only, so other genera will not be affected by this rust fungus. The soil does not need to be treated or removed. The fungus survives on plant mater-ial only, so proper sanitation of infected plant material is sufficient (removal from the site and disposal). Rust spores travel via wind and rain and they could be coming into the garden from surrounding areas. If plants become infected, you do not need to remove the entire tuber; cutting off the upper portion is sufficient and the tubers will sprout again next year. This can, however, weaken the plant and cause its demise if repeated annually. This Journal Article points to it as well. Studies on the Isolation and Growth of Plant Rusts in Host Tissue Cultures and upon Synthetic Media. II. Uromyces ari-triphylli Victor M. Cutter, Jr. Mycologia Vol. 52, No. 5 (Sep. - Oct., 1960), pp. 726-742 Published by: Taylor & Francis, Ltd. DOI: 10.2307/3755872 Stable URL: http://www.jstor.org/stable/3755872/ Jo Canning, Vancouver Island, BC, Canada _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/…