Symptoms and Pathogen Analysis of Sitting Sprout Disease in Chinese Orchids

During spring and summer,orchid plantswhen they are just sprouting and growing, suddenly some leaves lose water and shrivel, and on closer inspection,orchid plantsthe base of the new shoots has heart rot, the central leaf or a group of leaves can be pulled out, and in severe cases the pseudobulb and roots rot, so that the wholeorchid plantrots and dies. We customarily call this phenomenon sitting sprout (note: in Guangdong, orchid plants are called orchid sprouts). In the past, this disease was not definitively diagnosed, and some called it "bacterialsoft rotdisease", "base rot", "root rot", "phytophthora rot", and so on; Guangdong customarily calls it "sitting sprout disease". I attended the internationalorchidindustry symposium held in April 2004 at the Chencun Flower World in Guangdong, where Professor Lu Li? of the Taiwan Agricultural Research Institute's Pesticide and Toxic Substances Research Institute made a definitive conclusion, considering this to be a "genetic disease", caused by invasion of Fusarium spp., leading to yellow leaves, wilting, stem rot, and so on. Professor Lu has studied Chinese orchid diseases for more than twenty years and is a seniororchiddisease expert; his conclusion is authoritative. From 2002 to 2004, relevant mainland experts did a great deal of work on the occurrence and spread of sitting sprout in Guangdong Chinese orchids, pathogen isolation, and pathogenicity testing, and likewise determined that the pathogen of "sitting sprout disease" is Fusarium. Excerpted from "OrchidTreasure Book"