Table of Apple Rootstock Cultivar Susceptibility to Phytophthora spp.
Phytophthora spp.  


Table of apple cultivar susceptibility to Phytophthora spp.
(Source of information and credits provided at the bottom of the page.)

Apple rootstock cultivar Phytophthora resistance ratin
M.104 HS
M.106 HS
M.111 S-MR
M.2 MR
M.26 S-HS
M.4 MR
M.7 S
M.7a S
M.9 MR
Seedling MR

zMR = Moderately resistant. Specific control needed under high disease pressure.
S = susceptible. Control usually needed where disease is prevalent.
HS = highly susceptible. Control always needed where disease is prevalent. These cultivars should receive first priority when control is called for.

Data compiled by K. S. Yoder and A. R. Biggs from personal observations and the following sources:

Wilcox, W. 1990. Phytophthora crown, collar, and root rots. In: A. L. Jones and H. S. Aldwinckle, Eds., Compendium of Apple and Pear Diseases. APS Press, St. Paul, MN.