Disease Resistance

Montana is dry and we don't see much disease here. Healthy soil and a living soil food web do most of the work, and a lot of disease is a sign something else is off. Genetics still matter though, especially if you garden somewhere wetter than we do. Our disease resistance charts break it down plant by plant, and the research page has the university sources behind them.

For apples, Liberty and William's Pride resist all four of the big ones: scab, fire blight, cedar-apple rust and powdery mildew. Claygate Pearmain, Nova Easygro and St. Edmund's Pippin resist scab, cedar-apple rust and mildew, and Black Oxford resists scab, cedar-apple rust and fire blight. If you're in a really cold spot, Dolgo crabapple is hardy to zone 1b and resists fire blight, scab and mildew, and Chestnut and Centennial applecrabs are hardy to zone 2 and both resist fire blight.

Fire blight is the one that kills pear trees, so it's worth planting around. Harrow Sweet, Honeysweet, Seckel and Summercrisp all resist it. For stone fruit, Risingstar and Redstar peaches resist bacterial spot and brown rot, Toka plum resists bacterial spot and black knot, and Evan's Bali tart cherry resists black knot.

In the berry patch, Nova raspberry resists anthracnose, root rot, rust and spur blight. Titania black currant and Jeanne and Jahn's Prairie gooseberries resist anthracnose, blister rust and powdery mildew. For grapes, Sabrevois resists black rot, downy mildew and powdery mildew, and Itasca resists both mildews.