Submitted to: Acta Horticulture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 21, 2008
Publication Date: June 14, 2009
Citation: Omer, M.A., Locke, J.C., Frantz, J., Horst, L., Krause, C.R. 2009. Interaction of Calibrachoa and Selected Root and Foliar Pathogens in Greenhouse Setting. International Symposium on High Technology for Greenhouse Systems, June 14-19, 2009, Quebec City, Quebec Canada. p.145.
Calibrachoa (Calibrachoa x hybrida) is a popular annual ornamental that was introduced in the late 1990s by the greenhouse ornamental industry. Little is published about its interaction with pathogens commonly associated with greenhouse production. We report here for the first time the response of Calibrachoa to infection by pathogens that may be introduced in greenhouse production cycle through the use of infested soil, contaminated tools, infected cuttings, and contaminated irrigation water. Rooted cuttings of cv. Colorburst Violet were artificially inoculated with isolates from Phytophthora, Pythium, Verticillium and Botrytis. Symptoms expressed in response to infection included interveinal chlorosis of young leaves, wilting and necrotic root tips with fewer or no secondary or tertiary roots. Non-challenged plants had healthy root systems with an abundance of primary, secondary, and tertiary roots. We observed a 12 to > 80% decrease in root fresh weight in symptomatic plants compared to plants that showed no disease symptoms. All isolates from infected plants were recovered and identities confirmed. Greenhouse managers and clinicians should be aware that Calibrachoa is susceptible to several important plant pathogens and should scout regularly for them in order to exclude them as much as possible from their production systems.