Phytophthora Root and Crown Rots of Peach Trees in the Eastern Great Lakes Region

Symptomatic trees in many of these orchards had been diagnosed previously as suffering from winter injury or root asphyxiation following an excessively wet autumn and spring. When woody peach seedlings were transplanted into artificially infested potting soil and flooded for 48-hr periods at 2 wk intervals, P. cactorum and most isolates identified as P. cryptogea were highly virulent, causing > 90% root rot and a 60-100% incidence of crown rot; isolates of P. megasperma displayed more variable levels of virulence, causing 19-80% root rot and a 0-60% incidence of crown rot

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