Black spots on pansy and viola leaves

Your precious pansies and violas seem to be doing well until one day you notice that the leaves are covered in tiny black spots. The plants appear otherwise healthy and the spots themselves are difficult to see. However once you know they are there the evidence becomes glaring.

The spots can appear as either small, round pin pricks or irregular blotches. These are caused by one, and sometimes more of three specific fungi, namely Ramularia lactea, Ramularia agrestis and Mycocentrospora acerina.

There is some bad news as these fungal spores are only spread by rain over short distances and not wind-borne, so the likely source of the fungus is from the purchase of infected plants.That being said it is possible that wild pansies and violas may also provide sources of infection for garden specimens. To add another layer of bad news non-chemical controls only go as far as to avoid repeat planting on the same site to prevent the build-up of these pathogens in the soil. There is no specific chemical control for black spots on pansy and viola leaves however consider using Bayer Fungus Fighter Concentrate, Bayer Fungus Fighter Plus, Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun.

These fungal spores develop in humid, moist conditions and so as a precaution, and while it is not always easy always try to water from the base and avoid splashing leaves and flowers.

Be aware that without preventive measures these fungal spores can contaminate the soil for several years.