|SIKDAR, PARAMA - Washington State University|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2015
Publication Date: 11/1/2015
Citation: Sikdar, P., Mazzola, M. 2015. Managing quarantine-significant post harvest diseases in Pacific Northwest apple orchards. Phytopathology. 105:S4.127.
Technical Abstract: Phacidiopycnis washingtonensis and Sphaeropsis pyriputrescens are two recently reported quarantined pathogens that cause speck rot and sphaeropsis rot, respectively, in apple. Due to quarantine regulation, export of apple from Washington State to China was banned from 2012 through 2014. Previous studies demonstrated that pycnidia of P. washingtonensis and S. pyriputrscens survive on twig cankers of the pollinator ‘Manchurian’ crabapple, and serve as a primary source of inoculum to incite fruit infection in the orchard. The goal of this study was to evaluate orchard pruning as part of a systems approach to control speck rot and sphaeropsis rot in post-harvest storage. The research was conducted at 4 different locations in Washington State, and two treatments were compared: pruning cankered crabapple twigs at flower bloom followed by fungicide treatment at harvest and a no treatment control treatment. Fruits were harvested at commercial harvest dates, stored at 0°C in RA and disease development recorded up to 8 months post-harvest. It was observed that the pruning treatment followed by fungicide application was highly effective in controlling postharvest speck rot and sphaeropsis rot in storage. These findings are economically important to ensure uninterrupted export of disease free apple to international markets.