Increased Incidence of Erwinia Soft-rot on Calla Lilies in the Presence of Phosphorous
Source: European Journal of Plant Pathology, Volume 110, Number 3, March 2004 , pp. 293-298(6)
Abstract:Erwinia soft-rot is an important disease of many ornamental potted crops and is one of the most limiting factors in greenhouse calla lily (Zantedeschia spp.) production. Experiments were conducted to test the effect of phosphorous added to soil-less mixes or to nutrient solutions used for irrigation on soft-rot caused by Erwinia carotovora subsp. carotovora (Ecc). Soft-rot incidence increased to 51% when soil-less mix was amended with superphosphate in comparison to regular soil-less mix (no superphosphate added) (31%). In contrast, addition of phosphorous in the nutrient solution met the phosphorous needs of the plant without enhancing soft-rot. Plant height, fresh mass, and number of flowers per plant were greater in calla lilies irrigated with nutrient solution containing phosphorous than no phosphorous treatments. Similar results were obtained in tests conducted in a commercial greenhouse with larger sample size. No statistical differences were found between tubers sprayed with water (control) or with a 0.5 mM solution of KH2PO4 in laboratory experiments to determine the effect of phosphorous on tuber root development. In other experiments, tubers were sprayed with either water, a bacterial cell suspension 1 × 102 cfu ml−1, a solution of 0.5 mM KH2PO4, or a suspension of bacteria in KH2PO4. The results from these tests showed a significant increase of soft-rot development in tubers treated with the suspension of Ecc prepared in a solution of KH2PO4 relative to other treatments. Further laboratory tests indicated that enzymatic activity (polygalacturonase and pectate lyase) of Ecc increased when grown in the presence of phosphorous. These experiments suggest that increased soft-rot in the presence of phosphorous is due to increased virulence of Ecc.
Document Type: Research Article
Affiliations: 1: Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 4902 Victoria Avenue N., P.O. Box 6000, Vineland Station, ON, L0R 2E0 Canada (Phone: 613 7597816; ), Fax: 613 7597769, Email: Gracia-Garzaj@agr.gc.ca 2: Department of Plant Agriculture, University of Guelph, ON, L0R 2E0 Canada 3: Ontario Ministry of Agriculture and Food, 4890 Victoria Avenue N., Vineland Station, ON, L0R 2E0 Canada 4: United States Department of Agriculture, Agricultural Research Service, Sustainable Agricultural Systems Laboratory, BARC-West, Beltsville, MD 20705, USA 5: Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 4902 Victoria Avenue N., P.O. Box 6000, Vineland Station, ON, L0R 2E0 Canada
Publication date: 2004-03-01