Transmission and Management of Pathogenic and in Select Ornamentals.

Pathogenic and are phytobacteria that induce crown gall and leafy gall disease, respectively, resulting in undesirable growth abnormalities. When present in nurseries, plants infected by either bacterium are destroyed, resulting in substantial losses for growers, especially those producing plants valued for their ornamental attributes. There are many unanswered questions regarding pathogen transmission on tools used to take cuttings for propagation and whether products used for bacterial disease control are effective. We investigated the ability to transmit pathogenic and on secateurs and the efficacy of registered control products against both bacteria in vitro and in vivo Experimental plants used were × , × , and × for and × and 'Siskiyou' with . In separate experiments, we found secateurs could convey both bacteria in numbers sufficient to initiate disease in a host-dependent manner and that bacteria could be recovered from secateurs after a single cut through an infected stem. In in vivo assays, none of six products tested against prevented crown gall disease, although several products appeared promising in in vitro trials. Likewise, four compounds trialed against . failed to prevent disease. Sanitation and clean planting material remain the primary means of disease management.