Survival of apple rootstocks to natural infections of fire blight.
Survival of replicated rootstock plantings of apple trees (Malus domestica [M. pumila]) to fire blight (Erwinia amylovora) infection shows that a wide range of rootstock susceptibility exists. Trees on 'Malling 26' (M.26), 'Mailing 9' (M.9) and 'Mark' consistently had significant losses. Of the dwarfing rootstocks widely available commercially, 'Budagovsky 9' (B.9) survived well with productive trees, but was not resistant to fire blight infection. The following experimental rootstocks had good survivability with many live productive trees in one or more trials conducted in 1985, 1990 and 1994, at different sites in the USA: 'Poland 2' (P.2), 'Vineland 1' (V.1), 'Malling 27 EMLA' (M.27 EMLA), 'Budagovsky 491' (B.491), 'Budagovsky 409' (B.409), 'Vineland 7' (V.7), 'Vineland 4' (V.4) and 'Oregon Rootstock 1' (OAR1).