First report of Phytophthora capsici causing blight and root rot of Dendrobium candidum in China

Dendrobium candidum is a traditional Chinese medicinal that has pharmacological effects for improving immunity and anti-tumor (Li et al. 2011). In recent years, with the increasing health-care demand, wild D. candidum were domesticated artificially and tissue cultured seedlings were widely cultivated. Since 2014, about 10% to 15% typical basal stem and root rot disease had been observed on D. candidum in Guannan, Yunnan province. Disease symptom was upward and spread quickly. Stem and tap roots were completely rotted with brown to black lesions and the seedling plants died within a few days. Typical disease samples of stem and root rot were collected and used to isolate the possible pathogen. After rinsed by tap-water, infected tissues were surface sterilized in 70% ethanol for 30 s, washed three times with sterile distilled water, cut into small pieces and inoculated on Rye agar medium amended antibiotics, then incubated for 3 to 5 days at 25°C in the dark. A Phytophthora species was consistently isolate...