Buds question

[Alex]

I was looking at some photos on Paul's brilliant website, and noticed in one or two the buds have a particular appearance that I have on some of my own emerging buds at the moment, and have been wondering about. It is a sort of uneven colouring that is well illustrated in the Leda bud in the background (below). Does the panel think it has any significance, or is it just a normal variant of pigmented bud development?

Cheers,

Alex

P.S. I hope Paul will not mind me adding this quick screenshot from the Pleione website, it just seems better than the phone camera alternative from me! If there are copyright issues or similar, I can very easily remove it....

[Paul Cumbleton]

Hi Alex,
I have noticed this streaking on buds from time to time and almost invariably the flowers turn out streaked too - i.e. it is probably a sign of virus infection. Lacking colour, white flowers usually don't show symptoms of the virus in the flower but sometimes it is evident in the buds as in the picture you show and sometimes also in the leaves.

[Alex]

Hi Paul,

Thanks for this. I have it on several buds myself....would you consider this sort of symptom justification enough to throw a bulb away? Or would you want to wait to see streaking on flowers themselves or leaves?

As I have a number of somewhat similar ones, it's a big question for me. FWIW, I have noticed that the color change/streaking gets less distinct as the bud ages.

Thanks,

Alex

[karel_t]

Hi Alex,
Paul is right that this discoloration of bud-bractea may indicate a viral infection. After all this theme recur here each year. Visibility of this discoloration can change, according to the vitality and the disposition of each individual plant. We can't exactly say if is the plant viral or not without testing (PCR and electron microscope). However, this and any other unusual discoloration is very alarming. As I already wrote here, the virus may not always occur on the flowers. As Paul writes,  the pale and white flowers usually not show any visible symptoms. I'd advise you to insert plants into quarantine and if the discoloration will appear again next year, test them or destroy them.
Karel

[Alex]

As a follow up, do you believe that temperature stress *can* cause this appearance on buds or flowers? Or does that always give a more regular or symmetrical appearance? I have seen Several posts on this forum from yourself and others where it has been said that the presence of irregular streaking and other viral type symptoms does not tie in well with the presence or absence of virus by EM, suggesting other causes are possible.

I know we have this discussion quite often here, but it is an important one and it is as well to revisit it periodically to accommodate changing views and new information, in my view anyway. Mostly, as s grower, I just want to know how to manage such plants, so need a decent estimate of how likely a virus is, without access to diagnostic techniques.

Thanks very much,

Alex

[Alex]

Another quick follow up for Paul: in the older comments on virus in Pleiones (2008), you say that you are not convinced that color breaks are necessarily viral, and that such symptoms are not that well correlated with the presence of virus (http://www.srgc.net/forum/index.php?topic=1186.msg34756 4th message down). In the last year or two your comments on virus have become a bit more stringent and the overall view seems more conservative. My question is, did anything in particular change your mind? Is it the research from Karel or others, or personal experience? Just interested as i definitely detect a bit of a shift.

Cheers,

Alex

[karel_t]

To believe or not to believe - that is the Question! However, one thing is sure: there are a number of cases, when we found virus in plants like this one. Therefore, it is too foolish to believe that my plants are just oddly-coloured, but healthy. I think, in this case is always better to expect the worst. Unfortunately, without any objective tests we still stay on the spiritual level of 'faith'.
K.

[Alex]

Hi Karel,

Thanks for this. You put your finger on it there - although we have some information, mostly from your work, we don't have enough to properly understand the significance of all of these symptoms, and we must have faith - unfortunately, I'm not very good at that!

Still, i think your quarantine approach is sensible and pragmatic, although if symptoms disappear the following year I wouldn't be completely reassured the plant is virus free given what I've read here about the variable penetrance of viral infections. Perhaps, then, the only way is to dispose of anything with any symptom straight away, but that's tough.

Alex

[Alex]

Hi all, particularly Karel,

Moving on from buds, I have noticed a plant with the appearance below on its leaves. the outer (older) 2/3 of the leaf is very even and normal, but there are some pale streaks as you can see towards the centre. I know there are no definite answers, and quarantine is always wise, but do you regard this as suspicious for virus, or more likely due to nutritional deficiencies etc?

I must say, I'm starting to see potential virus symptoms everywhere now....

Thanks,

Alex

[Maren]

Hi Alex,

I've had that particular symptom in the past, diagnosed as a magnesium deficiency; managed to address it with an application of Epsom Salts.

[Alex]

Thanks, Maren - was it just the same as this with the streaks? I do have some Epsom salts, so will give it a go....

Alex

[Maren]

Hi Alex, it looked much like your plant.

[Alex]

Thank you, Maren. Epsom salts administered, let's see.

Cheers,

Alex

[karel_t]

Hi Alex,
I'm not thinking that these blotches are caused by virus, by my experience similar blotches are from quick develop of leaves and as plant ages, blotches usually disappear.
K.

[Alex]

Hi Karel,

Thanks very much for that.

Btw, I visited Ian Butterfield today, he mentioned you are visiting the week after next - it's a good display this year, you have a treat in store!

Alex