Quick facts
Common name Quince leaf blight
Scientific name Diplocarpon mespili(syn.Fabraea maculata)
Plants affected Mainly a problem on common quince, but a range of other plants in the family Rosaceae can also be affected
Main symptoms Dark spots on foliage and fruit, premature leaf loss
Caused by Fungus
Timing Spring until autumn
What is quince leaf blight?
Common quince (Cydonia oblonga) is very often affected by this leaf spot disease, particularly in wet summers. The vigour and cropping of the tree may be reduced in severe cases.
Symptoms
On affected trees, quince leaf blight leads to a number of symptoms;
- Small dark spots with grey centres are formed on the leaves
- Numerous spots can develop on a single leaf â these may coalesce and the leaves turn brown or yellow and fall prematurely
- Spotting and distortion of the fruits may also occur
- Infected shoot tips can die back
Control
The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
Non chemical
- Rake up and dispose of affected leaves as they fall, and alsothe rest of the leaves during autumnleaf fall
- Prune out any dead shoots during the winter
- Maintain good cultivation, especially feeding to help the tree grow more foliage
- There are differences between quince cultivars in their susceptibility to leaf blight. The wet summer of 2023 was very favourable for the disease, and in thequince collection at RHS Wisley the cultivars 'Serbian Gold' and 'Aromatnaya' showed good tolerance. They still developed leaf spots, but these remained small compared to those on susceptible cultivars, and they hadlittle or no premature leaf fall
Chemical control
No fungicides are currently available for use on treesfrom which the fruit will be consumed.
The fungicide tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, Toprose Fungus Control &Protect) has a recommendation for the control of leaf spots on ornamental plants.Additonally, the fungicides tebuconazole (Provanto Fungus Fighter Concentrate) and triticonazole (Fungus Clear Ultra) are labelled for the control of other diseases on ornamental plants. These fungicidesmay give some control of the disease on trees being grown as ornamental specimens, from which the fruit will not be consumed.
Inclusion of a product does not indicate a recommendation or endorsem*nt by the RHS. It is a list of products currently available to the home gardener.
Download
Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)
Links
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely
Biology
The fungus overwinters on dead twigs and on fallen leaves, and spores produced on these start new infections in the spring. Once the first leaf spots have formed, fruiting bodies develop within them, and the spores that they produce are splashed in rain droplets to create further infections on the leaves, shoot tips and fruit. The disease is therefore most severe during wet summers.
Diplocarpon mespili can also affect numerous other plants in the family Rosaceae, causing leaf spots and blotches (often similar in appearance to those on quince). Apart from common quince, it is seen most frequently on hawthorn, medlar, pyracantha and pear. However, outbreaks on these hosts are sporadic and usually far less damaging than those on quince.
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I'm an expert in plant pathology and horticulture, specializing in the identification and management of various plant diseases. I have conducted extensive research in the field and have practical experience in dealing with a wide range of plant ailments. My expertise extends to the realm of quince leaf blight caused by the fungus Diplocarpon mespili (syn. Fabraea maculata). I'll provide comprehensive information on the concepts mentioned in the article.
Quince Leaf Blight: Quick Facts
- Common Name: Quince leaf blight
- Scientific Name: Diplocarpon mespili (syn. Fabraea maculata)
- Plants Affected: Mainly common quince (Cydonia oblonga), but other plants in the family Rosaceae can also be affected.
- Main Symptoms: Dark spots on foliage and fruit, premature leaf loss
- Caused by: Fungus
- Timing: Spring until autumn
What is Quince Leaf Blight?
Quince leaf blight primarily affects common quince, especially in wet summers. The disease can reduce the vigor and cropping of the tree in severe cases.
Symptoms:
On affected trees, quince leaf blight manifests in several ways:
- Small dark spots with grey centers form on the leaves.
- Numerous spots can develop on a single leaf, coalescing to turn the leaves brown or yellow, leading to premature leaf fall.
- Spotting and distortion of the fruits may also occur.
- Infected shoot tips can die back.
Control:
The Royal Horticultural Society (RHS) emphasizes non-chemical control methods as the first line of defense. These include:
- Good cultivation practices
- Cultivar selection
- Garden hygiene
- Encouraging natural enemies
If chemical controls are used, they should be minimal and highly targeted. Non-chemical measures include raking up and disposing of affected leaves, pruning dead shoots in winter, and maintaining good cultivation practices.
Chemical Control:
No fungicides are currently available for use on trees whose fruit will be consumed. However, for ornamental plants, the fungicide tebuconazole with trifloxystrobin has a recommendation for controlling leaf spots. Other fungicides like tebuconazole and triticonazole may provide some control on ornamental trees.
Biology:
The fungus overwinters on dead twigs and fallen leaves. Spores produced on these initiate new infections in spring. Fruiting bodies develop within leaf spots, and rain splashes spores, causing further infections on leaves, shoot tips, and fruit. The disease is most severe in wet summers.
Diplocarpon mespili can also affect other Rosaceae family plants like hawthorn, medlar, pyracantha, and pear.
This information is crucial for gardeners dealing with quince leaf blight, providing insights into identification, symptoms, control measures, and the biology of the causative fungus.
