Control of bacterial soft rot of calla (Zantedeschia spp.) by pathogen exclusion, elimination and removal

Abstract

The incidence and severity of bacterial soft rot of calla (Zantedeschia spp.) tubers at harvest were substantially reduced by planting method, chemical control measures, and removal of infected plant material. Callas grown using a sawdust-shadecloth method had fewer soft-rotted plants and tubers than callas grown in soil. Dipping tubers before planting in an aqueous solution of 0.08% copper hydroxide, 0.12% thiram, plus 0.03% benomyl reduced plant and tuber losses from bacterial soft rot. Drenching plants during the growing season with an aqueous solution of 0.12% thiram, 0.08% copper hydroxide, plus 0.15% quintozene gave further control against rots. Weekly removal of rotting foliage and tubers during the growing season also reduced levels of plant and tuber soft rots. This study has demonstrated that effective control of calla soft rot can be achieved using disease management that combines appropriate pathogen exclusion, elimination, and removal methods. © 2005 Taylor & Francis Group, LLC.