Virus and Nutritional problems

Bessie · 2023-02-17T00:21:26+00:00

Continuing the conversation about virus, coming from the "Taking Dahlia Cuttings" thread... I found this video a beginner's overview of Dahlia virus. There's...

Juliarugula

Teddahlia Maybe it will pop up again at Parks someday. I was sort of hoping you’d chime it to tell me it’s a small plant, at least, but it doesn’t sound like it. Too bad.

JessieC I’ve probably lost about 10% this year, which is kind of what I was expecting. Pretty consistent with last year. It seems like this year I had more dud tubers that never sprouted, both in my own stock and in purchased tubers. I set aside replacements to pop in when the inevitable happened, which was a good idea. But next year, I need to plan my replacements better - there’s a few varieties I’m kicking myself for not saving the extra tubers/cuttings.

JessieC

Juliarugula Me too! I am so glad I figured out cuttings (thanks to the generous people here 😊) It makes it so much easier to pull the plug when you can fill that spot with a healthy plant. I will also plan for more extras next year. They make good gifts.
I’m most confused by the appearance of streaky foliage though. It would be so nice to find a local person who could walk me through what I’m looking at. Reading things on the internet can only get you so far, and then when you read that a staggering number of plants are virus positive, the whole thing seems futile. If my wonky looking ones came from less-experienced growers, I’d find it easier to toss them.
While it’s not super rare, I’m most pleased that I was able to find HH Miss White, and that I was able to make two backup cuttings. One of my HHMW tubers vaporized in the ground, and I didn’t really sweat it. I’ve got three growing now and they all look great!
Good luck!

Teddahlia

Miss White was named after a slot machine in an Indian casino called the Lucky Eagle. I do not gamble except on dahlia seedlings. We were there mostly for the buffet and Margaret would occasionally would play the slots. Miss White was not good machine for pay outs. It was a good name and it did win a medal.

MA_Dahlias

What a fantastically educational thread! I have a few plants that aren't looking their best at the moment and many who are thriving - I suppose I'd be bored if none of them needed attention! With a few I'm trying some different nutritional interventions, to see if it helps, but with this one dahlia, I don't know of anything other than a virus that would cause spotting. I'd truly appreciate the experience of others on this one! THANK YOU!

SteveM

MA_Dahlias Are those bottom leaves?

Juliarugula

MA_Dahlias it’s such a regular pattern - it’s like your plant has measles…

I’m curious about it too.

MA_Dahlias

SteveM Those are mid plant so far... the top leaves are showing fewer spots. This is the plant in question - sorry about the water, we had some good thunderstorms roll through last night!

SteveM

MA_Dahlias I have never had those exact same symptoms so I am just guessing. The spots look too even in spacing and size to be TSWV or DMV. When I see virus chlorosis it is usually (always?) splotchy with no consistent pattern. I have had magnesium deficiency of tomatoes that looked very similar to these but it started on the lowest leaves. Still, my best guess is that it is a nutritional deficiency of something, probably one of the micronutrients. If this were my plant and I had time to experiment, I would drench the soil around the plant with a solution of 1 tablespoon/gal of soluble Miracle Grow (or equivalent soluble fertilizer that included the micros), and repeat in a week. I wouldn't expect the spots to vanish but would hope the new growth did not have the symptoms.
I get a similar strange pattern on the bottom leaves of my Peaches-N-Cream plants when the leaves senesce or if the plant is under-fertilized.

JessieC

SteveM I get a similar strange pattern on the bottom leaves of my Peaches-N-Cream plants when the leaves senesce or if the plant is under-fertilized

Ok. I’ve been wanting to ask this question: is PnC (or any other variety) simply prone to weird looking foliage? I’ve got several PnC plants from varied but reliable sources, and there’s no rhyme or reason to which ones are exhibiting streaky leaf patterns. I tossed one out and put a photo in this thread earlier. Micronutrients seemed to help one, but I’ve got another one that looks vigorous and blotchy. Some are from my own tubers, which originated with a highly reputable source, new 2023 tubers from the same source, cuttings from said tubers, and one extra tuber that came as a bonus from a good (but admittedly not A+++) source. That last one is quite small still, but all the others have exhibited some weird foliage.
One other thing: I saw a photo the other day of a PnC from a nearby flower farm. I can see similar streaks in that plant too. Maybe I’m just deluding myself, but I’m hoping you’ll tell me that it’s just a trait of the plant. I didn’t see it in last year’s PnC plant (I only had one.)
Orange Globe is another one that shows odd foliage for me. It’s very dark green and curly, with some discoloration. I’d say these two lead me to doubt all the plants around them from time to time!
Thanks in advance 🙏🏻
This is the pic I saw the other day:

MA_Dahlias

SteveM That's exactly what I've done so far. Gave them a good dose of Jack's Classic Blossom yesterday, so I'll wait and see how it responds - lots of room for experimenting around here!! I'm trying to figure out the whole virus vs. nutrients issues and how they present themselves. I understand viruses can be "out run" by the plant for a while as they get bigger, so I'm not sure when to decide they are "better" from added fertilizer, or just bigger so better at fending off viral symptoms. Always something to figure out - I wish the viral tests were more affordable!

Bessie

I found an excellent video that teaches how to diagnose plant nutrients deficiencies.
https://youtu.be/Cq9tTqMxh2o

This video discusses optimizing phosphorus fertilization https://youtu.be/sAUlbcQQ3Q8

SteveM

Bessie I found an excellent video that teaches how to diagnose plant nutrients deficiencies.
https://youtu.be/Cq9tTqMxh2o

Thanks Bessie, a lot of good information! I like how he separated the deficiency diagnosis by their mobility.

Teddahlia

There are two points I would like to make: (1) A virus infection in a dahlia is only relevant if it inhibits the growth of the plant. If there are no symptoms or are very few symptoms the plant is resistant to the virus. Yes, the plant is infected and that virus can be passed on to a variety that could be negatively affected. Many varieties are permanently infected but show no symptoms. And of course that same variety may not be resistant to a different virus and if it gets that one, it may be all over. They selected about six viruses of the hundreds for the virus test program and where are the criteria for their selection? Could it be that some of these viruses seldom exhibit symptoms and really ought to be ignored as we ignore the hundreds of other viruses not included on the list of six? (2) I will post the other one later as it is lunch time.

NCDahlia

Interesting theory there. I tend to let things grow unless there is a clear an obvious problem, stunted growth etc as you mentioned Ted.

I think we all discussed on cubits about the whole clean stock vs importing stock (buying from others) and introducing it into our gardens. I do think dahlias are more resilient than we give them credit for. I have taken dahlias that voles have eaten the entire tuber and only left 1/2 inch of the crown and they rooted again. Trial and error it's what I like the best about growing plants. You just figure out what works for your growing environment the flowers are the reward.

I really think the main other dahlia issues people should obviously be aware of and avoid is the crown gall and leafy gall but you would be able to see LG easy and crown gall when you dig tubers.

calico20hill

In my experience Crown gall may not show up until the tubers have been overwintered. I found it on one of my potted tubers this spring, and was glad it had been potted...but I know it was not visible when I had potted it. I also had recieved a tuber from a very well known Breeder/Seller and Exhibitor of dahlias and he seemed to have no knowledge of crown gall 3 yrs ago and did not replace the tuber as I had expected. (No, I have not ordered any more from him, much as I would like to).

MA_Dahlias

Can anyone help with these symptoms that seems to be impacting a few dahlias in the patch. Plants showing this issue are surrounded by plants with no symptoms. At first I thought it had gotten dry and didn't rebound, but I've got probably four plants scattered around with similar necrosis. I'll do some digging on YouTube for possible nutrient causes, but thought I'd ask incase anyone else had seem the same thing. My first guess is it's a potassium issue, thought I've been doing a good job of feeding regular with a low nitrogen fertilizer.

Bessie

MA_Dahlias what part of the plant are the symptoms on? Uppermost, middle, lower leaves? Do all plants show the same damage on the same region of the plant?

MA_Dahlias

Bessie They seem to be mid to upper level leaves on all of the plants. The four or five plants that are affected do seem to have similar symptoms on about the same region of the plant, that inter-veinal necrosis. They kind of dry up from the edges toward the middle of the leaf with the impacted leaves being primarily in the middle part of the plant.

Bessie

MA_Dahlias my best guess is Potassium (K) deficiency. Potassium deficiency usually shows up on the older leaves, and the necrosis happens rapidly. If the symptoms were on my plants I'd treat with an all purpose water soluble fertilizer that contains micronutrients.

MA_Dahlias

Bessie Thanks Bessie! I have been giving them a soluble fertilizer, but perhaps not heavily enough. From a "gallons" perspective, how much water do you to allocate for each plant when you feed? I get the dilution per gallon math, very straight forward, but I do feel like I'm guessing when it comes to how much I'm supposed to be using per feeding on my entire patch. I wonder if I'm too frugal.

Bessie

MA_Dahlias there is no one right way to fertilize. From years of experience, I fertilize based on what the plants look like. I like to see leafy growth and nice dark green leaves(varies by variety) throughout the plant. For healthy growing plants I mostly use a soluble 24-8-16 fertilizer that contains micronutrients, mixed to recommended dose. Soil type plays a role in how the nutrients are available to the plant. I have a "sandy loan" soil that leaches out nitrogen during the rainy season. I used to have clay soil years ago and found that typically much less fertilizer is needed.
Fertilization of plants is a rather involved topic based on the plant nutrition needs, the soil and organic matter content, the growing environment coupled with plant water requirements, and the chemistry of soil fertilizers and soil amendments.

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