Q What are pansy leaf spots?
A A variety of fungi cause spots on pansies and violas, particularly winter-flowering varieties. Large, disfiguring black spots are likely to be caused by Mycocentrospora acerina; brown, scorched spots by Ramularia agrestis; and dark, greasy-looking spots with brown centres by Ramularia lactea.
Caption: Leaf spot tends to occur in mild, moist conditions
Q What plants do pansy leaf spots affect?
A These fungi can affect pansies, violas and violets, including wild species. Mycocentrospora also affects other genera, causing leaf spotting on a wide range of flowering plants, and root rot in carrots, parsnips and celery.
Q How do I recognise pansy leaf spots?
A Leaf spots appear as distinct, separate spots, whereas mildews create more irregular patches of discolouration.
Q What damage do pansy leaf spots do?
A Mycocentrospora can kill plants by rotting the crown. The other infections are generally confined to the leaves, so are largely cosmetic.
Q What is the life cycle of pansy leaf spots?
A While growing on the pansies, the fungi produce spores, which are generally spread by rain or in surface water. They can also produce resting spores that can survive for many years in dead plant remains in the soil, ready to infect new plants.
Q When do pansy leaf spot attacks occur?
A Leaf spots are most likely to develop in mild, moist conditions. The spores do not travel far, so infection will generally come from wild pansies or violets nearby, or from soil or compost where pansies have been grown before.
Q How do I control an attack of pansy leaf spots?
A Several general, systemic fungicides are approved for use on pansies and should help to control leaf spot diseases if applied when symptoms are first seen. These are myclobutanil, sold as Fungus Clear Ultra Gun (spray) Fungus Fighter Disease Control (spray) and Systhane Fungus Fighter (concentrate), and triticonazole, found in Scotts Fungus Clear Ultra (concentrate).
Q What are the organic options for controlling pansy leaf spots?
A Removing badly affected leaves will check the spread of the problem.
Q How do I prevent pansy leaf spots in future?
A Inspect plants carefully before buying to check there are no signs of leaf spot, or grow your own from seed. Avoid growing pansies or violas in soil or compost that has been used for them previously.
Caption: Raising your own pansies and violas for seed will help avoid leaf-spot problems