Common diseases of Apple trees

A large number of diseases occur in Apple trees in England because of the frequent rainfall that helps their spread and development.  The most effective method of prevention is to plant varieties that have resistance to the disease.  Where that is not possible, keeping a clean orchard by removing diseased plant parts can slow the spread.

Apple Scab is when the leaves are displaying brown or olive green spots and there are black spots on the fruit.  In severe cases, scab causes defoliation which weakens the tree, inhibits flower formation, and makes the tree vulnerable to other diseases.  Avoid growing Red Delicious, Cortland, McIntosh and Rome Beauty, as these are all susceptible to the disease.

Apple scab is spread from spores released from previously infected apple leaves that remain on the ground through winter and from infected trees nearby.  In order to reduce exposure to infections in the next growing season, in autumn, rake up and remove the leaves, debris and infected fruit.  Prune out twigs that are blistered too.

The most effective strategy for managing apple scab is to plant resisting varieties.  Several apple cultivars including, ‘Beauty of Bath’, ‘Cornish Aromatic’, ‘Duke of Devonshire’, ‘Encore’, ‘Epicure’, ‘Melba’, ‘Park Farm Pippin’, and ‘Wheeler’s Russet’,  are resistant to apple scab.

There are no fungicides currently being produced for use by home gardeners.

The infection can spread between touching fruit, in a cluster, even if some of the fruit was previously undamaged.  The effected fruit will either fall from the tree, or continue to hang in a mummified state.  Depending on the weather conditions at time of flowering, the severity of the disease can vary greatly from one year to the next.

The most effective way to manage the disease is by minimising the carry-over of pathogens by removing and disposing all of the rotted fruit as soon as you see it.  Also, if you see any rotted fruit hanging from the tree, remove and dispose of those too.  As birds are the main cause of the wounds inflicted on apples, allowing brown rot to occur, you could consider using a net to protect the tree.  Where possible, prune out and dispose of infected spurs and blossoms to reduce the amount of fungus available to infect the fruit.

There are no fungicides for Brown Rot available to amateur gardeners.

Brown Rot is a fungal disease found in Apples as well as some other popular fruit and ornamental trees. It gets its name from the spreading brown rot found in the fruit.  The disease starts by attacking fruit that has already been damaged by pets – especially codling moth and birds – or has been bruised.

The infection can spread between touching fruit, in a cluster, even if some of the fruit was previously undamaged.  The effected fruit will either fall from the tree, or continue to hang in a mummified state.  Depending on the weather conditions at time of flowering, the severity of the disease can vary greatly from one year to the next.

The most effective way to manage the disease is by minimising the carry-over of pathogens by removing and disposing all of the rotted fruit as soon as you see it.  Also, if you see any rotted fruit hanging from the tree, remove and dispose of those too.  As birds are the main cause of the wounds inflicted on apples, allowing brown rot to occur, you could consider using a net to protect the tree.  Where possible, prune out and dispose of infected spurs and blossoms to reduce the amount of fungus available to infect the fruit.

There are no fungicides for Brown Rot available to amateur gardeners.

Flyspeck and sooty blotch are two summer diseases of apple. These diseases are most common in wet summers, and although there is a dark fungal grown on the surface of the fruit, the eating or cooking quality is not affected.

Flyspeck appears as a group of tiny and sharply defined black dots. These groups are often circular and about half the diameter of a dime, but the specks can also be randomly distributed. Sooty blotch is another surface fungus that causes green, grey, or black stains that cover a large portion of the fruit surface. Flyspeck and sooty blotch are slow growing fungi. Visible symptoms take a month or more to appear after initial infection.

Sooty blotch and flyspeck are both favoured by high humidity, often occurring in unpruned, large trees with thick canopies, or trees located in a pocket where morning dew persists into the day. Warm, humid weather in August or September leads to higher risk of noticeable flyspeck and sooty blotch.

Sooty blotch and flyspeck are easier to prevent than scab.  One method is to prune regularly, creating a more open structure that allows for good circulation as this will discourage the growth of either disease.  Thinning the fruit will also allow more to air to circulate around them.

There are no fungicides available to home gardeners fur use against sooty blots and flyspeck.

Get in touch for an obligation free quote by phoning 07555 224 201 or 01488 50 50 58 or email us at info@naturallytrees.co.uk

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