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Missouri Environment & Garden



AUTHOR

Michele Warmund
University of Missouri
Division of Plant Sciences
(573) 882-9632
warmundm@missouri.edu

Scab Resistant Apple Cultivars Revisited

Michele Warmund
University of Missouri
(573) 882-9632
warmundm@missouri.edu

Published: December 1, 2011

Several scab resistant apple cultivars are currently available for planting, including Liberty, Pixie Crunch, Crimson Gold, Crimson Topaz, Freedom, Galarina, Querina, Enterprise, and Goldrush. Although each of these cultivars has immunity or resistance to apple scab, they have additional positive and negative attributes. Thus, it is important to match the cultivar with the characteristics you desire when selecting trees for planting. Because Missouri temperatures often reach 100°F in August, early ripening disease resistant cultivars are excluded. Also, some of following cultivars have not yet been evaluated in Missouri and they may have unidentified limitations to fruit production.

Liberty is a one of the older cultivars, released in 1978, that has broad resistance to apple scab, fire blight, cedar apple rust, and powdery mildew. Like all scab resistant cultivars, it is susceptible to other diseases and insect pests may infest leaves and fruits. However, Liberty is a standard scab resistant cultivar recommended for planting in Missouri. It has red fruit with a yellow background color that generally ripens around September 10 in central Missouri.

Pixie Crunch was developed by the cooperative breeding program of Purdue, Rutgers, and Illinois (PRI). These trees have a spreading growth habit with some bare wood on its leggy branches. Pixie Crunch is immune to apple scab, moderately susceptible to fire blight, and susceptible to downy mildew and cedar-apple rust. This red apple ripens about the same time as Liberty and the fruit tends to be small, but it has a crisp texture.

Crimson Gold and Crimson Topaz ripen around mid September. Crimson Gold is scab resistant, but it may be susceptible to other diseases. The fruit is a reddish- orange color with a yellow background and has a sweet/acidic flavor. Crimson Topaz has similar fruit color with striping. Trees of this cultivar have an upright growth habit, bear fruit on spurs, and are resistant to apple scab, but only moderately resistant to mildew and fire blight.

Freedom was the second scab-resistant cultivar released by the New York State Agricultural Experiment Station breeding program. However, trees are only moderately resistant to fire blight which is a limiting factor to apple production in Missouri. The fruit has a spicy flavor, is an orangish-red color, and the peel has prominent lenticels. In wet growing seasons, the fruit surface is rough with some black rot infections at lenticels.

Galarina was introduced from France and later evaluated and released by the Quebec apple breeding program. It has high tolerance to scab, but its susceptibility to other diseases has not been evaluated in Missouri. This cultivar has a sweet flavor and looks much like Gala, with medium to small reddish orange fruit color. Fruit is harvested in mid to late September.

Florina (also known as Querina) is another scab resistant cultivar that originated in France. It also has moderate resistance to blight and mildew, but is susceptible to cedar apple rust. Although its parentage includes Jonathan, its flavor has been described as mild and buttery. The dark red, medium-sized fruit ripens in October.

Enterprise is an older, but reliable cultivar that ripens in October. It is immune to scab, resistant to fire blight and cedar apple rust, and is moderately resistant to mildew. The fruit is tart and is medium to large with red color, but the peel tends to be tough.

Like Enterprise, Goldrush originated from the PRI breeding program. It is immune to apple scab, resistant to powdery mildew, moderately resistant to fire blight, but susceptible to cedar apple rust. It has medium to large yellow fruit with sweet/acidic flavor that tends to mellow when cold-stored. The fruit ripens in October after Enterprise.

Most of these scab resistant cultivars are available from nurseries on rootstocks that that produce relative large to very large trees such as M.26, M.7, and MM.111. However, M.26 is very susceptible to fire blight and therefore this rootstock is not recommended for planting in Missouri.

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REVISED: October 11, 2011