Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2005
Publication Date: 8/5/2005
Citation: Shishkoff, N., Senesac, A.F. 2005. Susceptibility to Phytophthora ramorum of roots and shoots of common container weeds [abstract]. Phytopathology. 95:S96.
Technical Abstract: Phytophthora ramorum is known to infect a number of ornamental plants grown in containerized culture. However, pots may also contain weeds, so it was useful to test eleven common container weeds for susceptibility to P. ramorum. These included Senecio vulgaris, Cardamine hirsuta, Chamaesyce maculata, Sagina procumbens, Epilobium ciliatum, Stellaria media, Oxalis stricta and Pteris, sp. Foliage was inoculated with water suspensions of approx. 3000 sporangia/mL and placed in a dew chamber for 3-4 days prior to evaluation. Roots were inoculated by pouring suspensions as 10 mL aliquots into pots and waiting at least 25 days before plating (washed or surface-sterilized for 5 min in 0.025% sodium hypochlorite). Of weeds tested, only Epilobium and Pteris showed foliar symptoms. The pathogen could also be isolated from the roots of Epilobium, whether washed or surface-sterilized, suggesting that roots were internally colonized. P. ramorum could be re-isolated in low numbers from the washed roots of various weeds, but not from surface-sterilized ones, suggesting superficial colonization of the rhizosphere.