EFFICACY OF HOT WATER AND CHEMICAL SEED TREATMENTS ON BACTERIAL SPECK OF TOMATO IN TURKEY

Bacterial speck, caused by Pseudomonas syringae pv. tomato (Pst), is an economically important disease of tomato, that causes yield loss of marketable fruit. Management of bacterial speck is a challenge in commercial nurseries, fields or greenhouses. This is due to the limited efficacy of current disease management strategies, since the pathogen acquires resistance to antibiotics and copper-based compounds in Turkey. The pathogen is seed- borne and no disease resistant tomato cultivars are commercially available. Therefore, it is essential to develop alternative disease control strategies. In this study, physical and chemical seed treatments that provide disease suppression were assayed individually or combined under climatic conditions and the colonization ability ofPseudomonas syringae pv. tomato on/in inoculated seeds was compared with untreated seeds. All seed treatments significantly reduced the Pseudomonas syringae pv. tomato population on seeds and significantly decreased disease incidence and disease severity. Mean bacterial populations on the plate dilutions was diminished up to 100% in hot water treated tomato seeds. The efficacies of treatments on disease incidence and severity provide evidence of significance and greater than 57%. Treatments did not significantly affect seed germination and seed germination ranged from 76% to 91%. Based on our results, we recommend that hot water seed treatment be used to combat bacterial speck as a first step of disease management in nurseries.