Phythophthera Root Rot Management


Phytophtora root rot management. From UMass Cranberry newsletter October 5, 2019.


Up to three applications of Phosphonate (eg., Rampart, Phostrol, Alude, Fosphite) or Phenylamide fungicides (eg., Ridomil Gold, Ultra Flourish) are currently recommended for this disease. Phosphonate fungicides are recommended for foliar applications; and phenylamide fungicides for ground application or chemigation. The first application is recommended between April 15th and May 15th, followed by a second application 60-90 days (around June 15th to August 15th) after the first. If you have any phytophthora root rot infested beds, the next application should be done after harvest, prefereably prior to November 15th. It is very important to improve the drainage before applying fungicides to affected beds.


         At the time of harvest, precautions should be taken to avoid the spread of the pathogen from infested beds to uninfested beds. Machinery, equipment, footwear, etc. should be cleaned thoroughly using steam of 10% bleach or 70% alcohol. The sequence of flooding the beds during water harvest should be adjusted to flood heavily infected beds last.