Epiphytic Survival ofPseudomonas syringaepv.tomatoon Tomato Transplants Shipped from Georgia

Abstract

Survival of P. syringae pv. [pathovar] tomato as an epiphyte occurred during shipment of symptomless tomato transplants from Georgia to Ontario, Canada. Disease occurred on these transplants in the field. Transplants inoculated in Georgia with 108 colony-forming units (cfu) per milliliter of P. syringae pv. tomato were assayed 1 h postinoculation, 24 h later in both Georgia and Ontario, after brief poststorage periods in Ontario, and finally after 7 days. Initial population levels of 105 cfu/leaf at 1 h declined to 104 cfu/leaf in Ontario and 102 cfu/leaf in Georgia but then increased to 107 cfu/leaf in Ontario and 106 cfu/leaf in Georgia. Changes in epiphytic population were not influenced by cultivar or storage period. Until more effective population measures are developed, current control practices using streptomycin and copper compounds should be adhered to rigorously, even during the apparent absence of bacterial speck.