There are several insects and diseases that can attack apples grown in Ontario. Apple producers must exercise some control over these problems or fruit losses may be excessive and economic production not possible.

Several cultivars are now available which have high resistance or field immunity to apple scab. Table 1 is a partial list of available scab resistant apple cultivars, and additional selections are presently being developed. Some of these cultivars also have resistance to other diseases (Table 2).

Table 1. Scab Resistant Apple Cultivars.

Year Released
1996AAFC, St. Jean, PQ
1980Agriculture Canada, SEF
Florina (Querina®)1977INRA, France
Liberty1978NYSAES, NY
Macfree1974Agriculture Canada, SEF
McShay1988Oregon State, Purdue & Illinois Universities
Moira1978Agriculture Canada, SEF
Murray1980Agriculture Canada, SEF
Nova Easygro1971Agriculture Canada, Kentville, NS
Novamac1978Agriculture Canada, Kentville, NS
Novaspy1986Agriculture Canada, Kentville, NS
Primevère1997AAFC, St. Jean, PQ & PRI
Richelieu1983Agriculture Canada, St. Jean, PQ
Rouville1983Agriculture Canada, St. Jean, PQ
Sir Prize1975PRI
Trent1979Agriculture Canada, SEF
William's Pride1988PRI
  • PRI - Cooperative introductions from the State Universities in Purdue, Rutgers and Illinois.
  • AAFC, St. Jean, PQ - Agriculture and Agri-Food Canada, St. Jean sur Richelieu, PQ
  • Agriculture Canada, SEF - Smithfield Experimental Farm, Trenton, ON (closed)
  • NYSAES, NY - New York State Agriculture Experimental Station, Geneva, NY
  • INRA, France - Institute National de la Recherche Agronomique, Angers, France

Apple scab caused by Venturia inaequalis (Cke.) Wint., is the most serious disease affecting apples. Growing cultivars resistant to apple scab eliminates the need for control of this fungal disease. Apple scab is not the only disease that can hamper apple production in Ontario. Powdery mildew incited by Podosphaera leucotricha (Ell. & Ev.) Salm, and the bacterial disease, fire blight incited by Erwinia amylovora (Burr.) are also of major concern.

Cultivars with resistance to the major early season diseases (apple scab, fire blight, powdery mildew, cedar apple rust) are now under development and a few which are moderately or highly resistant to these diseases have been released. However, combining resistance to several diseases in a new apple cultivar, as well as maintaining desirable fruit characteristics, has been a formidable task. The level of reported disease resistance and the quality of the fruit produced for disease resistant cultivars in outlined in Table 2.

Resistance to other, less prevalent diseases, has not been included in disease resistance breeding programs. Susceptibility of the cultivars listed here to such problems as black rot, sooty blotch, fly speck, quince rust and other diseases remains largely undetermined. Such diseases might limit the adaptablility of otherwise disease resistant cultivars in some locations if no fungicide sprays are applied.

Before a large planting of disease resistant apples is attempted, disease resistance, fruit quality, and most importantly, market acceptability should be evaluated under a grower's own set of circumstances. Because of the wide range of growing conditions in Ontario apple districts, the best way to evaluate these cultivars is to establish your own small planting including those cultivars of interest.


Figure 1. Liberty apples.


Figure 2. Freedom apples.

Table 2. Selected cultivars with demonstrated field resistance

to the diseases listed. Not all cultivars listed have been evaluated in Ontario. Where this is the case the information given is taken from the originating source.

CultivarApple ScabPowdery MildewFire BlightCedar Apple RustQuince RustBest UseHarvest SeasonStorage (months)
BelmacRMRUUUdessertlate Sept.3 - 4
BritegoldRRRSSdessertmid Sept.1 - 2
DaytonRMRMRSSdessertearly to mid Sept.1
EnterpriseRMRRRUdessertmid Oct.6
FreedomRMRRMRUdualearly Oct.1 - 2
Florina (Querina®)RUMRUUdessertUU
GoldrushRMRMRSUdessertlate Oct.5 - 6
JonafreeRMRMRSMRdessertearly Oct.2 - 3
LibertyRRRRMRdessertlate Sept.4 - 5
MacfreeRMRMRRSdualearly Oct.2 - 3
McShayRSUUUdessertmid Sept.2 - 3
MoiraRSSRSdualearly Oct.2 - 3
MurrayRRMRRSdessertlate Aug.< 1
Nova EasygroRRMRRSdessertlate Sept.2 - 3
NovamacRMRURSdessertearly Sept.3 - 4
NovaspyRMRUSSdualmid Oct.4 - 5
PrimaRMRMRSSdualmid Sept.1
PrimavèreRUUSSdessertmid Oct.6
PriscillaRRRRSdualearly Oct.2
Pristine™RRMRSUdessertearly Aug.1
RedfreeRMRMRRMRdessertlate Aug.1 - 2
RichelieuRUUSSdualearly Sept.2 - 3
RouvilleRUUUUprocessearly Sept.2
Sir PrizeRMRMRSSdualearly Oct.2 - 3
TrentRMRMRRSduallate Oct.6
William's PrideRMRMRRSdessertmid Aug.1 - 1.5

Note: Disease Resistance Ratings

R - resistant (no control necessary)
MR - moderately resistant (control may be necessary under severe disease pressure)
S - susceptible (control necessary in growing areas where the disease is prevalent)
U - unknown
Storage - months in refrigerated storage at 1° C.
Best use - processing: juice, sauce or pie fill - dessert: fresh fruit - dual: combined use
Harvest Date - observed or estimated under Ontario conditions

Table 3. Description of Apple Cultivars.

CultivarBrief Description of Major Attributes
BelmacResembles McIntosh, skin smooth and glossy with up to 90% red, slightly stripped over a green background colour. Flesh is white, medium to coarse texture, mild sub-acid. Cold hardy.
BritegoldYellow, medium to large size, sweet, flesh creamy yellow, slightly coarse, tender, and juicy. Bruises easily. Home garden use.
Dayton80 - 90% attractive glossy red over yellow background colour. Flesh pale yellow, crisp, juicy, firm, fine grained, and moderately acid. Home garden use.
EnterpriseMedium fruit size, washed 80 - 100% medium red on a very bright and glossy green-yellow ground colour. Flesh is fine grained, pale yellow to cream coloured, firm, crisp, sub-acid. Has potential as a commercial cultivar.
Freedom80% red strips on a yellow background, large size. Flesh is creamy, juicy, firm, medium fine grained, tender and moderately acid. Has potential as a commercial cultivar.
Florina (Querina®)Fruit 50% red on yellow ground colour, firm, small to medium size, sweet flavour. Whitish-yellow flesh, very crisp, low acid. Deserves further evaluation.
GoldrushFruit medium size, greenish-yellow to red blush at harvest, becoming entirely deep yellow in storage. Flesh is medium coarse grained, firm, crisp, pale yellow and non-browning. Flavour is complex, spicy and slightly acid at harvest.
Jonafree90 - 95% red, medium-sized with pale yellow flesh. Crisp, juicy, very firm, fine grained, mildly acid and pleasant aroma. Has potential as a commercial cultivar.
Liberty90% dark red with a yellowish background colour. Somewhat striped, moderately acid, flavour good. Flesh is yellowish, juicy, crisp, and fine textured. Has potential as a commercial cultivar.
Macfree75% medium red over greenish-yellow background, medium to small size. Flesh is juicy, white with a slight green tinge. Firm, moderately coarse, pleasant, moderately acid. Medium eating quality.
McShay70% dark red blush over a green background colour, similar to McIntosh. Flesh, moderately firm, fine texture, juicy, mild flavour and low acid.
MoiraRed, medium to small size, flesh creamy white with a green tinge. Medium eating quality.
MurrayRed, medium sized, flesh is soft, juicy, white and fine textured. Home garden use.
Nova EasygroStriped or washed, medium red over a green-yellow background. Medium sized, flesh is creamy white, moderately fine, firm, crisp, moderately juicy, and low acid. Home garden use.
NovamacFruit medium size, 50 - 90% blushed or striped medium red with a greenish-yellow background. Flesh is creamy white, fine, tender, moderately crisp, juicy, and moderately acid. Similar to McIntosh. Has potential as a commercial cultivar.
NovaspySimilar to Northern Spy, greenish yellow striped or blushed with dark red. Flesh creamy yellow, fine, very firm, crisp, moderately tender, juicy and moderately acid. Has potential as a commercial cultivar.
Prima60 - 80% bright red blush over a yellow background. Flesh is moderately acid, medium grained, crisp, and juicy. Tree lacks winter hardiness. Home garden use.
PrimavèreFruit bright and glossy dark cardinal red, slightly conical. Flesh is moderately coarse grained, pale green to white, firm, crisp. Has commercial potential.
Priscilla70 - 90% bright red blush over a light yellow background. Flesh is crisp, medium grained, juicy, mild flavour and low acid. Fruit size can be small. Home garden use.
Pristine™Fruit medium size, pale green-yellow at harvest, maturing to deep yellow, with moderate orange blush. Flesh is pale yellow, crisp, medium to fine grained, medium acid to sweet.
Redfree80 - 90% glossy medium red on a yellow background. Flesh is firm, light cream, medium grained, crisp, juicy, mild flavour, low acid. Uneven ripening. Has potential as a commercial cultivar for late August to early September.
RichelieuFruit 50 - 60% medium red, striped over green to light yellow ground colour, medium in size. Flesh white, tender, juicy, fine texture, mild to sub-acid.
RouvilleFruit large, 75 - 80% medium red, lightly striped, over pale green to yellow ground colour. Flesh is white, tender, slightly coarse, and sub-acid.
Sir PrizeYellow, can have a slight red blush, can russet. Large, bruises easily, flesh is juicy, crisp, and very tender. Poor pollenizer. Home garden use.
TrentRed, medium to large in size. Flesh is firm, juicy, cream coloured with greenish tinge, and slightly coarse. Prone to bitter pit.
William's PrideModerately bright dark red on green-yellow or pale yellow background. Medium to large size, flesh is light cream, medium grained, mildly acid, very crisp and firm. Multiple pickings required. Home garden use.