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When I began to grow apples, I wanted to grow them without sprays.
Here is the kind of information that I would have found very useful when starting out.
Bear in mind that the information is from my observations. While I believe it to be correct, it is possible that I may have been supplied with the wrong varieties, or I may have muddled my notes, or I might have made a typing error.
Common diseases
Aphids
Green or pink colours, with occasional blacks. Pink ones are the most troublesome. Green ones are the most common. Cause curling on the leaves and distorted shoots, which impairs photosynthesis, makes the tree look messy and protects the aphids in the curled-up leaves. They prefer the young leaves. Aphids secrete honeydew, which attracts ants. The honeydew drips onto leaves and fruits, which can become cause black moulds. These moulds are only superficial and not causing serious harm, except a slight reduction in light getting through to the leaves.
Heavy and prolonged rain washes aphids off the leaves, so dry spells are when they're most numerous.
Varieties of apples that flower (and leaf-out) early seem to miss the worst of the aphid attacks because the aphid populations are quite low early in the season (but early-flowering apples can suffer frost damage, although some are resistant to frost).
Aphids can be squirted with a water pistol, which will control their numbers. Alternatively, natural predators will come along, although ants will guard the aphid colonies and may drive off predators.
Hoverfly larvae are small, flattened, ribbed, yellow-orange maggot-caterpillar like creatures. They start off barely visible and end up about half-inch long.
Parasitic wasps, like tiny, black gnats - they do not attack humans. The adults inject an egg into the body of an aphid and the wasp develops inside, until the aphid bursts and the wasp flies away.
Wasp-infected aphids turn brown-black colour a day or two before they pop - and often the infected aphid leaves the colony, to wander off by itself, which can allow you to transfer some infected aphids to another aphid-infested plant in the hope that the hatching wasps will help.
Occasionally, ladybird larvae appear. They look more like tiny, black, six-legged scorpions.
Very occasionally, lacewing larvae appear. They are like pale-coloured, elongated, ladybird larvae and the lacewing larvae can move very fast when they want to.
Finally, spiders. The webs of the numerous baby spiders can catch large numbers of the winged aphids as the aphids try to colonise new plants.
A special type of aphid attacks apples; woolly aphid.
Furry white masses that resembles mould, clustered on young shoots, pruning cuts or other damaged bark. Some woolly aphids migrate to attack the roots.
The "wool" protects them from predators and I find that the parasitic wasps seem to be the best predator of woolly aphids.
The aphids cause bark swellings and root swellings. Those swellings often split (especially in cold or wet weather), exposing the tree to rot-type damage. Canker may enter the wounds, which can be a serious problem for varieties with low canker resistance.
Canker
Fungal spores enter damaged areas of bark. Most severe when it is wet and is greatly increased by the presence of woolly aphids. Canker causes the bark to split, flake off and turn red-ish. Often, the canker has a sunken, cracked, black-ish middle. On susceptible varieties, the canker may spread up-and-down the branch, “unzipping” and flaking off the bark as it travels, or it can encircle the branch, preventing sap flow - and the branch dies.
Cutting out the cankered areas is the only cure for susceptible varieties, although some resistant varieties will manage to wall-off and limit the canker by themselves. Choosing varieties some canker resistance is desirable, especially if the rootstock/apple variety is known to be susceptible to woolly aphid.
Powdery mildew
Common in the lower-rainfall areas. Unlike most fungi, it thrives in dry conditions.
Young leaves are most susceptible. Seen as a white, powdery coating on leaf surfaces and often causes leaves to be small, distorted and grey-green coloured. Cutting off infected leaves as soon as the mildew is seen can reduce the amount of mildew that season.
Hibernates in buds and comes out of hibernation when infected buds open in the spring. White marks on the bark around a bud often indicate hibernating mildew. Cutting off whitened areas will remove the fungus. Affected leaves or flowers may be small, pale and often have the white powder coating, although it can take a few days for the powder (spores) to develop. Infected flowers are not fertile.
Choosing varieties with some resistance is the only defence.
Scab
Particularly common with long periods of rain.
Young leaves and fruit are most susceptible and get less susceptible as the season progresses.
Causes dark brown patches on the leaves or fruits, although fruit scab often seems to be a bit darker in colour than leaf scab. Scab lesions may merge and engulf the whole leaf or fruit. Badly scabbed leaves and fruit will split. In the middle of the dark brown patches, it may be possible to see tiny black sporing structures.
Controlling scab is not easy, although scabbed fruit can usually be eaten or stored. Some people recommend raking up and burning all the leaves in the autumn, but if you’re not using sprays, probably the best control is choosing a resistant variety.
Common rootstocks
Apples are grafted onto a rootstock, which allow the production of apple trees with known characteristics - such as to control the eventual size, and to control how soon an apple starts to channel it's energy into producing fruit.
M27
Patio containers or dwarf bushes.
Extremely slow growing - 5ft.
Moderately susceptible to Woolly aphid.
Only requires minimal pruning.
My need to have fruits removed in the early years, to prevent stunting.
Needs very good soil and adequate moisture. May not survive without feeding and watering.
Canker-prone apple varieties not ideal on M27, due to need for regular watering and woolly aphid damage being infected by canker.
M9
Mainly for cordons.
Slow growing - 7ft.
Very susceptible to Woolly aphid.
Needs good, moist soil.
Will easily be uprooted in windy weather, unless staked.
Produces better quality fruit than other rootstocks.
Canker-prone varieties should be avoided on M9 for the same reasons as M27.
Tolerates wet soil.
M26
Bushes and cordons.
Moderate growing - 9ft.
Moderately susceptible to woolly aphid damage.
Will grow in most soils that don’t dry out.
MM106
Half-standards or bushes.
Moderately vigorous - 12ft.
Will grow in poor soils, but will need regular watering for the first few years in the drier eastern side of England.
Resistant to woolly aphid.
Causes early flowering in my area - by about two pollination groups, as compared to M26.
MM111
Standards, half standards or bushes.
Vigorous -14ft
Will grow in poor soil, but may need regular watering for the first two years in the drier eastern side of England. Roots are very efficient at gathering water, so MM111 is good for dry areas or light soils.
Resistant to woolly aphid.
May cause early flowering - perhaps by one pollination group as compared to M26.
M25
Standards or half-standards.
Very vigorous - 18ft.
Will grow almost anywhere, but may need regular watering for the first year or two in the drier east of England.
Tolerant of woolly aphid.
On poor soil and the drier parts of the UK, final height can be halved. In warm and damp areas, on good soils, the final height can be doubled.
The variety grafted onto the rootstock plays a part in the growth rate and final size. Strong growing varieties can be grafted onto weaker rootstocks and weak growing varieties onto stronger rootstocks, to compensate.
Some apple varieties that I grow, or have grown, on an estimated scale of 1-5, with 1 being weaker, earlier flowering etc. Low canker/scab/mildew resistance (levels 1 or 2) might struggle in the long-term, without chemicals.
Woolly aphid resistant rootstocks reduce canker - may enhance canker score by one level.
Annie Elizabeth
Vigour 4
Canker 4
Scab 4
Mildew 4
Pollination period 4
Ashmead Kernel
Vigour 3
Canker 4
Scab 4
Mildew 4
Flowering 4
Bramley
Vigour 5
Canker 4
Scab 4
Mildew 4
Flowering 3
Court Pendu Plat
Vigour 1
Canker 3
Scab 4
Mildew 4
Flowering 4
Crawley Beauty
Vigour 2
Canker 4
Scab 5
Mildew 4
Flowering 5
D’Arcy Spice
Vigour 1
Canker 4
Scab 4
Mildew 4
Flowering 3
Discovery
Vigour 2
Canker 4
Scab 4
Mildew 4
Flowering 2
Egremont Russet
Vigour 2
Canker 5
Scab 4
Mildew 4
Flowering 1
Ellison Orange
Vigour 3
Canker 1
Scab 4
Mildew 4
Flowering 2
Fiesta(Red Pippin)
Vigour 1
Canker 3
Scab 3
Mildew 4
Flowering 3
Golden Delicious
Vigour 3
Canker 3
Scab 3
Mildew 4
Flowering 4
Grenadier
Vigour 2
Canker 5
Scab 5
Mildew 4
Flowering 3
Howgate Wonder
Vigour 4
Canker 3
Scab 4
Mildew 4
Flowering 4
James Grieve
Vigour 2
Canker 2
Scab 3
Mildew 5
Flowering 2
Liberty
Vigour 3
Canker 2
Scab 4
Mildew 4
Flowering 4
Meridian
Vigour 2
Canker 3
Scab 3
Mildew 4
Flowering 2
Pinova
Vigour 1
Canker 3
Scab 4
Mildew 4
Flowering 3
Reverend Wilks
Vigour 2
Canker 4
Scab 4
Mildew 4
Flowering 1
Saturn
Vigour 3
Canker 2
Scab 4
Mildew 4
Flowering 4
Spartan
Vigour 3
Canker 1
Scab 3
Mildew 4
Flowering 4
Tydeman Late Orange
Vigour 4
Canker 4
Scab 4
Mildew 4
Flowering 3
Winston
Vigour 3
Canker 5
Scab 4
Mildew 4
Flowering 4
Winter Gem
Vigour 3
Canker 4
Scab 4
Mildew 4
Flowering 3
Worcester Pearmain
Vigour 3
Canker 2
Scab 3
Mildew 5
Flowering 3
Here is the kind of information that I would have found very useful when starting out.
Bear in mind that the information is from my observations. While I believe it to be correct, it is possible that I may have been supplied with the wrong varieties, or I may have muddled my notes, or I might have made a typing error.
Common diseases
Aphids
Green or pink colours, with occasional blacks. Pink ones are the most troublesome. Green ones are the most common. Cause curling on the leaves and distorted shoots, which impairs photosynthesis, makes the tree look messy and protects the aphids in the curled-up leaves. They prefer the young leaves. Aphids secrete honeydew, which attracts ants. The honeydew drips onto leaves and fruits, which can become cause black moulds. These moulds are only superficial and not causing serious harm, except a slight reduction in light getting through to the leaves.
Heavy and prolonged rain washes aphids off the leaves, so dry spells are when they're most numerous.
Varieties of apples that flower (and leaf-out) early seem to miss the worst of the aphid attacks because the aphid populations are quite low early in the season (but early-flowering apples can suffer frost damage, although some are resistant to frost).
Aphids can be squirted with a water pistol, which will control their numbers. Alternatively, natural predators will come along, although ants will guard the aphid colonies and may drive off predators.
Hoverfly larvae are small, flattened, ribbed, yellow-orange maggot-caterpillar like creatures. They start off barely visible and end up about half-inch long.
Parasitic wasps, like tiny, black gnats - they do not attack humans. The adults inject an egg into the body of an aphid and the wasp develops inside, until the aphid bursts and the wasp flies away.
Wasp-infected aphids turn brown-black colour a day or two before they pop - and often the infected aphid leaves the colony, to wander off by itself, which can allow you to transfer some infected aphids to another aphid-infested plant in the hope that the hatching wasps will help.
Occasionally, ladybird larvae appear. They look more like tiny, black, six-legged scorpions.
Very occasionally, lacewing larvae appear. They are like pale-coloured, elongated, ladybird larvae and the lacewing larvae can move very fast when they want to.
Finally, spiders. The webs of the numerous baby spiders can catch large numbers of the winged aphids as the aphids try to colonise new plants.
A special type of aphid attacks apples; woolly aphid.
Furry white masses that resembles mould, clustered on young shoots, pruning cuts or other damaged bark. Some woolly aphids migrate to attack the roots.
The "wool" protects them from predators and I find that the parasitic wasps seem to be the best predator of woolly aphids.
The aphids cause bark swellings and root swellings. Those swellings often split (especially in cold or wet weather), exposing the tree to rot-type damage. Canker may enter the wounds, which can be a serious problem for varieties with low canker resistance.
Canker
Fungal spores enter damaged areas of bark. Most severe when it is wet and is greatly increased by the presence of woolly aphids. Canker causes the bark to split, flake off and turn red-ish. Often, the canker has a sunken, cracked, black-ish middle. On susceptible varieties, the canker may spread up-and-down the branch, “unzipping” and flaking off the bark as it travels, or it can encircle the branch, preventing sap flow - and the branch dies.
Cutting out the cankered areas is the only cure for susceptible varieties, although some resistant varieties will manage to wall-off and limit the canker by themselves. Choosing varieties some canker resistance is desirable, especially if the rootstock/apple variety is known to be susceptible to woolly aphid.
Powdery mildew
Common in the lower-rainfall areas. Unlike most fungi, it thrives in dry conditions.
Young leaves are most susceptible. Seen as a white, powdery coating on leaf surfaces and often causes leaves to be small, distorted and grey-green coloured. Cutting off infected leaves as soon as the mildew is seen can reduce the amount of mildew that season.
Hibernates in buds and comes out of hibernation when infected buds open in the spring. White marks on the bark around a bud often indicate hibernating mildew. Cutting off whitened areas will remove the fungus. Affected leaves or flowers may be small, pale and often have the white powder coating, although it can take a few days for the powder (spores) to develop. Infected flowers are not fertile.
Choosing varieties with some resistance is the only defence.
Scab
Particularly common with long periods of rain.
Young leaves and fruit are most susceptible and get less susceptible as the season progresses.
Causes dark brown patches on the leaves or fruits, although fruit scab often seems to be a bit darker in colour than leaf scab. Scab lesions may merge and engulf the whole leaf or fruit. Badly scabbed leaves and fruit will split. In the middle of the dark brown patches, it may be possible to see tiny black sporing structures.
Controlling scab is not easy, although scabbed fruit can usually be eaten or stored. Some people recommend raking up and burning all the leaves in the autumn, but if you’re not using sprays, probably the best control is choosing a resistant variety.
Common rootstocks
Apples are grafted onto a rootstock, which allow the production of apple trees with known characteristics - such as to control the eventual size, and to control how soon an apple starts to channel it's energy into producing fruit.
M27
Patio containers or dwarf bushes.
Extremely slow growing - 5ft.
Moderately susceptible to Woolly aphid.
Only requires minimal pruning.
My need to have fruits removed in the early years, to prevent stunting.
Needs very good soil and adequate moisture. May not survive without feeding and watering.
Canker-prone apple varieties not ideal on M27, due to need for regular watering and woolly aphid damage being infected by canker.
M9
Mainly for cordons.
Slow growing - 7ft.
Very susceptible to Woolly aphid.
Needs good, moist soil.
Will easily be uprooted in windy weather, unless staked.
Produces better quality fruit than other rootstocks.
Canker-prone varieties should be avoided on M9 for the same reasons as M27.
Tolerates wet soil.
M26
Bushes and cordons.
Moderate growing - 9ft.
Moderately susceptible to woolly aphid damage.
Will grow in most soils that don’t dry out.
MM106
Half-standards or bushes.
Moderately vigorous - 12ft.
Will grow in poor soils, but will need regular watering for the first few years in the drier eastern side of England.
Resistant to woolly aphid.
Causes early flowering in my area - by about two pollination groups, as compared to M26.
MM111
Standards, half standards or bushes.
Vigorous -14ft
Will grow in poor soil, but may need regular watering for the first two years in the drier eastern side of England. Roots are very efficient at gathering water, so MM111 is good for dry areas or light soils.
Resistant to woolly aphid.
May cause early flowering - perhaps by one pollination group as compared to M26.
M25
Standards or half-standards.
Very vigorous - 18ft.
Will grow almost anywhere, but may need regular watering for the first year or two in the drier east of England.
Tolerant of woolly aphid.
On poor soil and the drier parts of the UK, final height can be halved. In warm and damp areas, on good soils, the final height can be doubled.
The variety grafted onto the rootstock plays a part in the growth rate and final size. Strong growing varieties can be grafted onto weaker rootstocks and weak growing varieties onto stronger rootstocks, to compensate.
Some apple varieties that I grow, or have grown, on an estimated scale of 1-5, with 1 being weaker, earlier flowering etc. Low canker/scab/mildew resistance (levels 1 or 2) might struggle in the long-term, without chemicals.
Woolly aphid resistant rootstocks reduce canker - may enhance canker score by one level.
Annie Elizabeth
Vigour 4
Canker 4
Scab 4
Mildew 4
Pollination period 4
Ashmead Kernel
Vigour 3
Canker 4
Scab 4
Mildew 4
Flowering 4
Bramley
Vigour 5
Canker 4
Scab 4
Mildew 4
Flowering 3
Court Pendu Plat
Vigour 1
Canker 3
Scab 4
Mildew 4
Flowering 4
Crawley Beauty
Vigour 2
Canker 4
Scab 5
Mildew 4
Flowering 5
D’Arcy Spice
Vigour 1
Canker 4
Scab 4
Mildew 4
Flowering 3
Discovery
Vigour 2
Canker 4
Scab 4
Mildew 4
Flowering 2
Egremont Russet
Vigour 2
Canker 5
Scab 4
Mildew 4
Flowering 1
Ellison Orange
Vigour 3
Canker 1
Scab 4
Mildew 4
Flowering 2
Fiesta(Red Pippin)
Vigour 1
Canker 3
Scab 3
Mildew 4
Flowering 3
Golden Delicious
Vigour 3
Canker 3
Scab 3
Mildew 4
Flowering 4
Grenadier
Vigour 2
Canker 5
Scab 5
Mildew 4
Flowering 3
Howgate Wonder
Vigour 4
Canker 3
Scab 4
Mildew 4
Flowering 4
James Grieve
Vigour 2
Canker 2
Scab 3
Mildew 5
Flowering 2
Liberty
Vigour 3
Canker 2
Scab 4
Mildew 4
Flowering 4
Meridian
Vigour 2
Canker 3
Scab 3
Mildew 4
Flowering 2
Pinova
Vigour 1
Canker 3
Scab 4
Mildew 4
Flowering 3
Reverend Wilks
Vigour 2
Canker 4
Scab 4
Mildew 4
Flowering 1
Saturn
Vigour 3
Canker 2
Scab 4
Mildew 4
Flowering 4
Spartan
Vigour 3
Canker 1
Scab 3
Mildew 4
Flowering 4
Tydeman Late Orange
Vigour 4
Canker 4
Scab 4
Mildew 4
Flowering 3
Winston
Vigour 3
Canker 5
Scab 4
Mildew 4
Flowering 4
Winter Gem
Vigour 3
Canker 4
Scab 4
Mildew 4
Flowering 3
Worcester Pearmain
Vigour 3
Canker 2
Scab 3
Mildew 5
Flowering 3
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