Planting disease resistant apple cultivars can make your life much easier, as you won't be spraying all the time. The down side to this is that you will have fewer cultivars to choose from. Some of the most delicious and complex flavored apples are not disease resistant. However, there are now many disease resistant apples that taste quite good. There are many lists available for disease resistant apples. Beyond the lists, however, are some apples that show at least some resistance.
An extensive list of disease resistant apple cultivars and their resistance profile can be obtained from the Home Orchard Society..
This is a heavy producing apple tree. The apples are red, crisp, and juicy. It is scab and mildew resistant. Ripeness is achieved in late august to early September.
Liberty ripens in early September with a stripy red over a yellow background.It is a moderately tart, all-purpose apple with the best resistance profile you can find.
Enterprise apples are pretty, blushing red apples. They are crisp and juicy and improve flavor with a few months storage. They are resistant to scab, fireblight, cedar apple rust and mildew. Enterprise ripens in October.
A heavy bearing tree discovered in Aberdeen, Washington, Wynoochi ripens in early August and has a delicious full bodied flavor.
I saw this apple in early August.The apples were on the smaller side, Yellow with a red blush. It was very clear of scab. It tasted very sweet. It is supposed to be immune to scab and fireblight.
This one is resistant to apple scab and cedar apple rust with good resistance to fireblight and powdery mildew. The one I saw had fewer apples, but the ones on it were quite good sized. It is a red apple with a rich aromatic flavor. Early August is the ripening time.
Grow this one instead of golden delicious! It is a nice yellow apple yet bigger than golden delicious. It is sweet, and a good fresh eating or baking apple. It is highly scab resistant and somewhat mildew resistant. Harvest late September to mid October.
I'm not sure where you can get this heritage apple. I saw it in the Home Orchard Society apple orchard. It had huge apples on a small tree. The apples were mostly green color. Although I find no listing that this is a scab resistant cultivar, the apples I saw had no scab showing even though this was one of the worst years ever for scab. It has a sweet flavor with good acid. It ripens in mid-September.