One method of reducing fire blight on crabapples is to plant disease-resistant clones. Colorado State University has been conducting research for over 20 years to evaluate crabapples for ornamental characteristics and disease resistance.
The trees being tested receive minimal irrigation and maintenance, pruning sucker sprouts and dead wood removal. No insect or disease control is done. Six clones have proven superior for fire blight disease-resistance; Malus ‘Velvet Pillar’, M. ‘Ralph Shay’, M. ‘Adams’, M. ‘Robinson’, M. ‘Louisa’, and M. ‘David’.
All six of these clones have persistent fruit and have shown good fire blight resistance.