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Quince leaf blight is caused by the fungus Diplocarpon mespili. In wet seasons it can cause severe leaf spotting and premature leaf fall, whilst fruit may also be spotted and distorted.
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.
On affected trees, quince leaf blight leads to a number of symptoms;
No fungicides are currently available for use on trees from which the fruit will be consumed.
The fungicides tebuconazole (Bayer Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Bayer Fungus Fighter Plus), and triticonazole (Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun) are labelled for the control of a number of diseases on ornamental plants and, whilst not mentioning quince leaf blight specifically, may 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 endorsement by the RHS. It is a list of products currently available to the home gardener.
Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)
Chemicals: using a sprayerChemicals: using safely and effectivelyChemicals: storing and disposing safely
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.
MedlarPowdery mildew Quince
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