Cyclamen leaf disease

[Gerry Webster]

Does anyone know what this is? I suspect a virus infection. The brown marks appear just as the flowers are going over & eventually the whole leaf turns yellow & dies. So far confined to C. graecum. (Ignore the white marks - they are traces of fungicide).

[Lesley Cox]

Without knowing much about such things, my first thought is some kind of mould and I'd probably try a fungicide to see if that stopped further marks.

[Gerry Webster]

Without knowing much about such things, my first thought is some kind of mould and I'd probably try a fungicide to see if that stopped further marks.

Lesley - that was my first thought too, hence the traces of fungicide visible in the photo. I'm continuing to treat with Carbendazim but I'm uncertain as to whether it is having any effect. There seems to be no relevant information on the internet.

[Darren]

I have been thinking about this and think the timing is interesting. I often get marks on leaves caused by botrytis spreading from fading flowers resting on them. Given the recent weather and the habit of cyclamen shedding pollen grains as the flower falls I wonder if these are speckles caused by botrytis starting on fallen pollen grains? The marks look like groups of tiny spots, which would fit this idea.

[Gerry Webster]

I have been thinking about this and think the timing is interesting. I often get marks on leaves caused by botrytis spreading from fading flowers resting on them. Given the recent weather and the habit of cyclamen shedding pollen grains as the flower falls I wonder if these are speckles caused by botrytis starting on fallen pollen grains? The marks look like groups of tiny spots, which would fit this idea.

That's an interesting idea Darren. However under a hand-lens the marks appear continuous (rather than spotty) though they only appear on the upper surface of the leaves - I think they are dead tissue. I always remove fallen flowers &, interestingly, one of my  plants in which the flowers never actually fall but just flop onto the leaves & shrivel has no sign of the problem. Thanks to Tony Willis I have been in contact with another cyclamen grower who has the same problem on the same species. We both think it is a fungal attack & - touch wood - fungicidal treatment seems to be stopping the spread, though it's early days yet.

[Gerry Webster]

The most recent view, from the RHS, is that this is damage from thrips. I'm not entirely convinced - their description of the symptoms does not exactly correspond with what I see. Maybe the symptoms are variable? I'd be interested to hear the opinions of other forumists.

[Ezeiza]

Thrips are attracted by blue. Easy to make a sticky trap.

[cycnich]

Hi Gerry
          I have around 80 graecum in pots and I get these symptons on and off on different plants. It does not appear to cause any long term damage and the same plants are clean the following year. I put it down to temperature, moisture and watering. It is unsightly but nothing to worry about at least with me anyway. It is not confined to graecum I have had it on other species as well and it always dissapears. Regards Pat.

[Gerry Webster]

Hi Gerry
          I have around 80 graecum in pots and I get these symptons on and off on different plants. It does not appear to cause any long term damage and the same plants are clean the following year. I put it down to temperature, moisture and watering. It is unsightly but nothing to worry about at least with me anyway. It is not confined to graecum I have had it on other species as well and it always dissapears. Regards Pat.

Thanks Pat - that's reassuring. It only appeared on the early flowering/leafing forms of graecum. Whatever caused it has disappeared since later forms show no symptoms at all.
Regards, Gerry