Cucumber Mosaic Virus

[claire]

Hi,

I was wondering whether you could point me in the direction of some good photos of leaves with cucumber mosaic virus?

I have a couple of white cucumber plants (still on the kitchen windowsill) that I have grown from seed and the lower leaves on both are fading and drying out to a crisp before falling off (or me pulling them off). The top leaves look fine.

Is this cucumber mosaic virus? If yes, how do I treat the plants? Will it affect my courgettes (seedlings not showing yet as only planted a few days ago)?

If not, is it too much/little light? water? heat? something else?

Thanks

[gardening_guru]

Hello Claire,

I don't know where you can find any decent photos, it could be Cucumber Mosaic Virus, but from what you have described, it does not sound as if your cucumber plants are showing any of the classic symptoms yet. I would expect to see puckered, mottled leaves that turn yellow with time. The whole plant will have stunted growth. Is it possible that these leaves could have been scorched on the windowsill? Is the windowsill very hot and sunny? Remember, those lower leaves were the first to appear and would have been quite vulnerable to sun scorch.

Can you quarantine these two cucumber plants? Wait to see what develops because if it is Cucumber Mosaic Virus you will have to destroy the plants, as the virus is not treatable.

Regards, George.

[claire]

Yes, the windowsill does get pretty hot so hopefully that is all the problem is ... was .... the plants are now looking rather unhappy outside (too much of a shock I think!). Maybe I should give them up as a bad job and buy some young plants instead! Thanks for your advice though, at least I can learn from it next year! Best wishes,

[claire]

came across this article that suggests it might be something called verticillium wilt:

http://www.ext.nodak.edu/extpubs/plants ... .htm#wilts

[Fiona]

I was wondering if I had cucumber mosaic virus on my courgette as well. I am growing one plant indoors in a large pot. Each time a leaf appears, it shrivels and dies. This has happened to the first five or six leaves. Do I have to destroy it? I am so disappointed!

Fiona.

[gardening_guru]

Hello Fiona,
Courgette plants are also susceptible to Cucumber Mosaic Virus, but don't throw the plant away until you are sure. As stated before I would expect to see puckered, mottled leaves that turn yellow with time. The whole plant will have stunted growth. Does your corgette plant have these symptoms? Tell me about where you are growing it indoors, if it is still alive I would certainly plant it outside now as all danger of frost has passed, it may be protesting at the fact that it is still indoors! Was the plant siiting in a saucer of water? Was enough air getting to the roots or were they possibly waterlogged? Was the plant sat on a very hot and sunny windowsill where the young leaves were getting scorched? The more information you can give me, the more chance I have of solving this.

Regards, George.

[Fiona]

Hi George,

Thanks for your reply. I live in a flat and don't have a garden, but the courgette is in a very large pot on an enclosed sun terrace. It mostly gets the sun in the morning. The soil is moist but the plant isn't sitting in water.

I think about three leaves are completely dead - beige coloured, a bit curled under, not even a hint of green. Two leaves have some light beige and grey-coloured flecks and one of these is dry at the edge and beginning to curl under. One new leaf is coming up, but I know it will go the same way as the others! The plant's growth is stunted because no growth ever seems to get the chance to flourish.

I still have some seeds left. If I have to ditch this one, is it too late to try planting another one? What should I use to disinfect the (plastic) pot if I reuse it?

Sorry for all the questions!

Fiona.

[gardening_guru]

Hello Fiona,

It sounds as if it could be Cucumber Mosaic Virus, if I were you I would dispose of this plant. Scrub the pot, washing-up liquid should be sufficient. Can I ask where the seed came from? Was it seed harvested from the fruit of a plant that you had grown previously? Or was it purchased from a seed supplier? The thing is, I'm just wondering if the parent plant had cucumber mosaic virus. Seed purchased from a reputable supplier should be certified disease free. You could sow some more seed now, just be aware that could actually get too hot during the hottest summer months for successful germination you will also, of course have a later crop of courgettes.

Sorry for all the questions!

George.

[Fiona]

Hi George,

I can't thank you enough for your help! I bought the seeds from Wilkinson's (!) and are Wilko's own brand (courgette black beauty). It does have a cash-back promise, but no guarantee of being disease free.

Can alpine strawberry get cucumber mosaic virus? Most of my large leaves on that have died, although I have just pruned them all off and the younger leaves are looking healthy just now, so am not sure that this is going the same way as the courgette and at the moment am hoping that it was just a small blip. Since I have removed the leaves, I can't remember in any detail what they looked like. There is one younger leaf that is turning yellow and dry at the edges. It is placed in my hallway and I did wonder if it was too dark, so I have moved it to the windowsill in my hallway instead. I bought it from the local market.

Thanks again,

Fiona.

[Fiona]

Oh, I think my alpine strawberry had spider mites. I know, before I wiped it away, there was cobwebby stuff, and when I looked at my aubergine plant, there was also cobwebby stuff and I could see the mites crawling all over the web. I then remembered about the existence of spider mites. I have treated both plants and am hoping both will do well now!

Thanks,

Fiona.

[gardening_guru]

Hello again Fiona,

It sounds as if it was the spider mites that were the problem with the Alpine Strawberries then. If it was warm in the hallway they would have bred at a much faster rate. If you can sit all pot plants on top of trays filled with constantly damp pebbles this will help a lot. Red spider-mite like dry, hot conditions. Damp pebbles will make the air around the plants damp and humid, red spider-mite hate that. This is one of the reasons why greenhouse paths are often hosed down and kept constantly damp.
As for the courgettes, I don’t want to question the quality of Wilkinson seed but I do know that the following courgette varieties have demonstrated good resistence to Cucumber Mosaic Virus:
‘Defender’
‘Supremo’
‘Tarmino’
Maybe you could try one of those next time…

Regards, George.