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Having been a bad year for scab (despite me living in one of the drier parts of the UK), I decided to study and document the extent of scab on my apples.
None of my varieties escaped scab entirely, but many showed strong resistance to damage. I have never sprayed them with chemicals, so any disease prevalence is completely natural.
My varieties were chosen to suit dry areas, where powdery mildew is a big problem - so they have good levels of natural resistance to powdery mildew, with scab as the second priority and no regard for canker resistance.
Several distinct types of scab attack were noticeable:
1. Pinpoint specks about 1mm across.
Typically 5% of total leaf area killed.
2. Medium sized blotches about 1-3 mm across.
Typically 10% of total leaf area killed.
3. Large lesions several mm across which leave tattered holes in the leaves.
Typically 15-20% of total leaf area killed.
4. Large lesions several mm across which merge together and kill the leaf.
Typically 25-30% of total leaf area killed.
Generally, the total amount of leaf area destroyed is proportional to the type of scab observed.
The following is my estimate of scab damage to the leaves (not fruits) on my plants - scored between 1-4, as per the above generalised categories. A score of 0 would have been reserved for varieties with no scab.
The fruits of russets tend to be more scab resistant than the leaves.
In alphabet order......
Annie Elizabeth: 1
Ashmead's Kernel (russet): 1
Bramley 20: 2
Court Pendu Plat: 2
Crawley Beauty: 1
D'Arcy Spice (russet): 3
Discovery: 1
Egremont Russet (russet): 2
Ellison's Orange: 1
Fiesta: 2
Golden Delicious: 3
Grenadier: 1
Howgate Wonder: 2
James Grieve: 1
Liberty: 1
Meridian: 3
Pinova: 3
Reverend Wilks: 2
Saturn: 4
Spartan: 3
Tydeman's Late Orange: 1
Winston: 2
Winter Gem: 2
Worcester Pearmain: 1
I hope that's of interest, but please don't base a major planting decision entirely on my findings!
FB.
None of my varieties escaped scab entirely, but many showed strong resistance to damage. I have never sprayed them with chemicals, so any disease prevalence is completely natural.
My varieties were chosen to suit dry areas, where powdery mildew is a big problem - so they have good levels of natural resistance to powdery mildew, with scab as the second priority and no regard for canker resistance.
Several distinct types of scab attack were noticeable:
1. Pinpoint specks about 1mm across.
Typically 5% of total leaf area killed.
2. Medium sized blotches about 1-3 mm across.
Typically 10% of total leaf area killed.
3. Large lesions several mm across which leave tattered holes in the leaves.
Typically 15-20% of total leaf area killed.
4. Large lesions several mm across which merge together and kill the leaf.
Typically 25-30% of total leaf area killed.
Generally, the total amount of leaf area destroyed is proportional to the type of scab observed.
The following is my estimate of scab damage to the leaves (not fruits) on my plants - scored between 1-4, as per the above generalised categories. A score of 0 would have been reserved for varieties with no scab.
The fruits of russets tend to be more scab resistant than the leaves.
In alphabet order......
Annie Elizabeth: 1
Ashmead's Kernel (russet): 1
Bramley 20: 2
Court Pendu Plat: 2
Crawley Beauty: 1
D'Arcy Spice (russet): 3
Discovery: 1
Egremont Russet (russet): 2
Ellison's Orange: 1
Fiesta: 2
Golden Delicious: 3
Grenadier: 1
Howgate Wonder: 2
James Grieve: 1
Liberty: 1
Meridian: 3
Pinova: 3
Reverend Wilks: 2
Saturn: 4
Spartan: 3
Tydeman's Late Orange: 1
Winston: 2
Winter Gem: 2
Worcester Pearmain: 1
I hope that's of interest, but please don't base a major planting decision entirely on my findings!
FB.
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