Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2006
Publication Date: 4/26/2006
Citation: Herder, K., Turechek, W. 2006. Evaluating hot-water treatment as means for eradicating xanthomonas fragariae in strawberry nursery stock. BARC Poster Day. Interpretive Summary:
Technical Abstract: Angular leaf spot is an important disease in California nursery production. The European and Mediterranean Plant Protection Organization (EPPO) lists X. fragariae as an A2 quarantine pathogen. Nurseries wishing to export plants to European countries must maintain certain phytosanitary standards. The potential of hot water treatment for disinfesting or killing viable cells was determined by dispensing 1 ml aliquots for each of 4 representative isolates of X. fragariae in microcentrifuge tubes and submerging tubes in water heated to 36, 40, 44, 48, 52, and 56 C for 1, 2.5, 5, 10, 15, 30, 60, 120, 240, 360 and 480 min. Bacteria were serially diluted to determine the proportion surviving heat treatment. Plants of the varieties ‘Camarosa’ and ‘Diamante’ were subjected to a similar range of treatments to test their sensitivity to heat; plants were potted and rated for growth characteristics. Bacteria exposed to 56 and 52 C were killed completely after 15 and 60 min exposure, respectively; both treatments killed plants. Results showed that bacteria exposed to 44 C for 240 min or 48 C for 120 min reduced populations greater than 95%. The same treatments minimally affected vegetative growth of plants, but flowering was adversely affected. However, hot water treatment is intended for nursery production, where flowering is unimportant. Heat treatment of nursery stock may supplement standard production practices for producing pathogen-free stock. Future research will scale the method to the production level.