A review of apple scab-resistant varieties for commercial growers

Many tasty and attractive apple varieties are available that have good resistance to apple scab disease, but may be prone to other disorders.

Pixie Crunch is a popular apple for U-pick due to the crisp texture, sweetness, attractive color and smaller size suited to children.

Pixie Crunch is a popular apple for U-pick due to the crisp texture, sweetness, attractive color and smaller size suited to children.

Apple varieties are available with decent to excellent resistance to apple scab, the most important fungal disease in rainy climates. Fruit quality of many of these scab-resistant varieties is quite good. Some of these scab-resistant varieties resemble more traditional varieties to some extent. Some of them are not recommended for fresh market, as noted in the tables below.

It is generally recommended by Michigan State University Extension that at least a limited fungicide program for apple scab be used on scab-resistant varieties in order to help lessen the potential for the scab pathogen to overcome the plant genes that give resistance. Fungicides may also be needed to provide protection against various other diseases such as cedar apple rust or powdery mildew, depending on the variety. These are noted in the following tables. All apple varieties are susceptible to sooty blotch and fly speck disease. It is usually more efficient to plant scab-resistant varieties separate from non-resistant varieties in order to manage fungicide programs for both apple types appropriately.

Most apple varieties use the same Vf gene for resistance, and scab strains resistant to this gene have been found in Europe, New Zealand, Indiana, Illinois and Ohio. Other sources of scab resistance such as Vr, VM and VA are present in some varieties such as Liberty and provide additional resistance. Some apple varieties such as Honeycrisp and Akane have decent resistance to apple scab, but are not immune. Suncrisp has some resistance to scab, but is significantly susceptible to fire blight.

The following tables summarize characteristics of scab-resistant apple varieties that may be of value to commercial growers. The focus here is on those with better quality. It is good to remember that customers generally prefer the traditional, non-scab resistant varieties, and in general commercial growers should limit the size of these plantings until they can establish consumer demand. Many farm markets have worked for years to replace traditional varieties with these scab-free varieties with limited success. Several of these varieties may be grown and marketed successfully for other uses such as processing for apple sauce, apple butter and sweet and hard cider.

Table 1. Harvest order of apple varieties with significant scab resistance and comparison with non-resistant reference varieties

Scab-resistant varieties

Non-scab-resistant reference varieties

Pristine -70 FB*
William’s Pride -55
Redfree -49 FB
Prima -28
Initial -26
Priscilla -14
Crimson Crisp -11 FB
Jonafree -7
Dayton -7
Scarlet O’Hara -7 FB
Pixie Crunch -7
Galarina
Crimson Topaz -3 FB
Liberty -3
Sir Prize 0
Eden 0
Freedom +10
Juliet +14
Sundance +18
Enterprise +33
Winecrisp +35
Goldrush +49

Yellow Transparent -78
Zestar!, Sansa -35
Jonamac -25
Imperial Gala -19
Marshall Macintosh -15
Honeycrisp -11
Cortland -5
Campbell Redchief +0
Golden Delicious +4
Empire +8
Ida Red +13
Northern Spy +15
Cameo +19
Crispin +23
Braeburn +40

*Numbers are the approximate ripe days (- = before, + = after) relative to Campbell Redchief Red Delicious. FB = fire blight prone variety.

Table 2. Detailed descriptions of selected scab resistant or scab-tolerant apple varieties.

Variety

Description

Akane (Tokyo Rose)

Somewhat Jonathan-like in appearance and flavor, bright red blush, medium sized fruit. Some susceptibility to fire blight, not totally resistant to apple scab. Medium-sized apple, good flavor, harvests shortly after Gala.

Crimson Crisp (Co-op 39)

80% deep cherry red. Relatively clean, medium size, round, smooth finish and yellow flesh. Tart/sweet, crisp texture, thick skin. Ripens mid-season and slightly before Red Delicious. Good storage, eye appeal and flavor make this a popular apple for u-pick and farm markets for fresh market.

Crimson Topaz

70-80% red/orange stripes on yellow back, ripens about four days ahead of Red Delicious. Medium-sized fruit, crisp, juicy flesh. Suitable for fresh market, fire blight-prone, may need a fall spray for nectria canker.

Eden

80% medium-red slight stripe on yellow green back, mac-like flavor but firmer, round, sometimes lopsided, medium to large, juicy, crisp, fine-textured white flesh, non-browning, slice and processing, ripens in Red Delicious season, fruit hangs on tree into winter.

Enterprise (Co-op 30)

Large, 80% glossy, medium-dark red on green/yellow background. Fine-textured cream to light yellow flesh. Productive, looks like a Rome, not for fresh market due to the thick skin and medium eating quality. Used as a Northern Spy substitute for processing, resistant to fire blight and cedar apple rust, moderately resistant to powdery mildew and stores well.

Galarina

Medium red with strips, conical shape with lobes, small to medium-sized. Yellow/white, fine-textured flesh, somewhat Gala-like. Ripens two weeks after Gala, fruit have better shelf-life than Gala, fruit hangs on tree into winter, potential for ice wine production.

Goldrush (Co-op 38)

Rough finish, yellow/slight green skin and firm flesh. Spicy flavor, resistant to powdery mildew, moderately resistant to fire blight and susceptible to cedar apple rust. Late (early November) ripening, excellent storage.

Jonafree (Co-op 22)

Red skin, productive, somewhat Jonathan-like. Very firm, not prone to bitter pit or Jonathan spot. Susceptible to fire blight and cedar apple rust. Less acid and firmer than Jonathan, late September ripening.

Juliet (Co-op 43)

70% striped medium-red blush on yellow-green background, smooth finish, white to slightly cream flesh, juicy, and sweet/low acid. Resistant to mildew, somewhat aromatic, maintains good firmness in storage. 2.5- to 3-inch diameter, round and somewhat flat.

Initial (X 6163)

Red blush on yellow, medium to large fruit with conical shape. Triploid (so is pollen sterile), prone to fruit drop, marketed for use in hard cider and for deer food plots.

Liberty

80% dark red, slightly striped skin on yellow background. Flesh is fine-textured, yellow/white, crisp, somewhat Mac-like appearance and flavor, but with better shelf-life. Resistant to cedar apple rust, moderately resistant to fire blight, productive, early bloom.

Nova Easygro

Cortland/McIntosh-like, does better in cooler climates, very sweet, moderately juicy. Moderately resistant to cedar apple rust and powdery mildew, moderately susceptible to fire blight.

Novamac

Mac-like, 70% medium-red blush/stripe on greenish yellow background. Medium-sized fruit, cream-white, fine-textured, medium crisp and acid flesh. Resistant to cedar apple rust, moderately resistant to powdery mildew.

Novaspy

Northern Spy-like, but not quite equal quality or storage life. Dark red stripes and blush on greenish yellow background. Cream to yellow flesh with fine texture, very firm, crisp, medium acid, juicy, ripens five days before Northern Spy.

Pixie Crunch (Co-op 33)

Nearly solid red on green-yellow background, low tendency to russet. Small fruit, crisp, juicy, sweet/tart complex flavor, medium storage life. Moderately resistant to fire blight and frogeye leafspot, some biannual bearing tendency, susceptible to powdery mildew and cedar-apple rust. Popular as u-pick apple for children.

Prima (Co-op 2)

Somewhat Jonathan-like, dark red blush on yellow green background, resistant to cedar apple rust.

Pristine (Co-op 32)

Yellow type, early, better quality than Lodi or Transparent, somewhat fire blight susceptible

Redfree (Co-op 13)

Somewhat Jonathan-like quality and appearance, susceptible to fire blight, better resistance to powdery mildew, cedar-apple rust, and fire blight than Jonathan.

Scarlet O’Hara (Co-op 25)

Large, over 3-inch diameter, round, 80% medium red/orange blush, light yellow to cream flesh, very firm and crisp. Fruit hangs well, mild to spicy pleasant flavor and juicy. Moderate resistance to powdery mildew, highly resistant to cedar apple rust, highly susceptible to fire blight. Long storage; flavor improves in storage.

Sundance (Co-op 29)

Very large, round, somewhat conical, yellow skin. Resistant to cedar apple rust, moderate to heavy cropping, some stem bowl russet, very susceptible to black rot (frogeye leaf spot). Stores well, spicy flavor.

Williams Pride

Somewhat like Red Delicious, medium dark red on pale yellow to slightly green background. Decent size and quality for an early Red Delicious-like apple. Mild flavor, short storage life, relatively crisp for early apple, productive, has shown excessive water core and some bitter pit in some years. Resistant to cedar apple rust, moderately resistant to powdery mildew and fire blight.

Winecrisp (Co-op 31)

80-100% dark purple-red, juicy, crisp, cream colored flesh apple, somewhat Winesap in appearance and flesh characteristics. Prone to scarf-skin russet, productive, 2.25- to 3-inch fruit has some tendency to drop, stores well. Like Winesap, this apple is more suited for processing.

 Other scab resistant-varieties:

  • Belmac
  • Britegold
  • Florina Querina
  • Priam
  • Florina
  • Baujade Macfree
  • Prima
  • Trent
  • Wolf River
  • Sir Prize
  • Res Rajka
  • Ras Resi
  • Res Releika
  • Res Goldstar
  • Super Mac
  • Freedom
  • Dayton

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