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These two Griffina plants have started to grow leaves that are streaked with yellow.  They are usually a very deep green color.  What do you think is wrong with them?  I use a 20-20-20 fertilizer at about ¼ to ½ strength for most waterings, then plain watering as a rinse on occasion.  They grow well and send up spikes regularly even with discolored leaves.  I cannot detect any insect pest infestation on them.  I recently repotted them and the roots and bulbs appear healthy.  Do they have a virus?  None of my other plants, including my other Griffinias, have ever exhibited this discoloration and I use the same fertilizer regimen for them. 

I hate to make a mistake and throw away favorite plants that might be treatable. But, if they have a virus, they have to go.

Thanks for your help.




 

The coloration looks too regular to be virus, although it could be. I would also expect some, even if very minor, irregularity in the leaf shape/form.
My guess for this season would be that they are objecting to being disturbed. I would give them until next growing season to see if the problem persists.

Even if it is virus, it needs a sap-sucker to move the virus around between plants.

Quote from: CG100 on November 11, 2024, 11:47:34 PMit needs a sap-sucker to move the virus around between plants

Yes, but they are all too common. I imagine they like soft leaves more than hard glossy ones.

Griffinia Leaves, What's Going On?
https://www.pacificbulbsociety.org/pbslist/2010-August/2m53ts58u746ggo0b4d9mt4rk7.html

seemingly the leaves are sensitive to changes in the environment.

The PBS wiki has a section on plant viruses.

https://www.pacificbulbsociety.org/pbswiki/index.php/virus

There's even a sentence with the Genus Griffinia mentioned. 

"Virus in Phaedranassa, Eucrosia, Eucharis, Stenomesson, Griffinia and Eustephia shows as longitudinal ridges (those leaves are perfectly flat if healthy), besides the mosaic stripes."

A photo of a Phaedranassa with virus is included in this section.

Alas, the wiki also states: "Virused plants may show symptoms such as streaked or mosaic patterns on flowers and foliage. Leaves and stems can be twisted, distorted, and necrosed. Some apparently healthy plants do not show viral symptoms and only under stress that a latent virus may begin to show. In other cases, there are plants that do not show signs of disease at all."

My plants do not appear to have longitudinal ridges beside the discolored stripes.  But, I'm still nervous about them because I know what they used to look like before presenting like the ones in the photo above.

So, perhaps there's another way to approach this topic.  If you (anyone reading this topic) had plants like mine in the photo above, how long would you keep them? [Because the sap-suckers are all too common.]

Thanks!

Virus in plants is common, even desired in some plants - many variegated plants carry a virus that causes the variegation, for instance (very many, perhaps all, variegated plants, apart from ones naturally so, that come variegated from seed, will carry virus).

I have no idea about current stocks of Nerine cultivars, but go back maybe 20 years and very many popular ones carried a heavy virus load, but did not really show any major problem in terms of growth.

I had an Amaryllis belladonna for a few years, bought from a commercial source, and I am pretty sure that that arrived with a virus infection as leaf distortion and marking gradually got more extensive. Being a winter-grower perhaps as much as anything, I never saw aphids on it and the virus has not obviously spread.

Personally, with your plants as they are currently, especially as it is after repotting, I'd wait and see.

All that said, apart from variegation, how many reports of virus infection are reports of proven fact? How many are guesswork and supposition?

Seemingly you could pay to have the plants tested for virus [1] - about $100. Maybe cheaper to buy new plants. Interesting that there are cheap lateral flow tests for plant virus's - but points to the fact you have to know the type of virus.

Electron microscope images of the virus would be great addition to the PBS wiki.


[1]
https://bpp.oregonstate.edu/plant-clinic/submit-sample/services-and-fees

I looked into having them tested for virus and it is just not worth the cost.  I can purchase 6 or 7 new plants, including the cost to ship them for price of viral testing. And, if the lab doesn't happen to test for the particular virus your plant has, you are back to where you started.

I hate to give up on cherished plants. The leaves and flowers on these plants are very nice. I'll give them some more time, but if they don't improve by Spring, I'll probably toss them and purchase new plants to be on the safe side.

I wonder where the virus came from. What would make a nursery able to avoid a source that you could not. How would you get rid of a reservoir of it.

Cheery questions 8-)

Nurseries will scrupulously control insect pests and in many/most plants, turnover will be high.

You are also making a huge assumption that commercial nurseries avoid infections. That said, plants with supposed virus infections are very far from common in enthusiasts' collections.

Hello Bern,
Having followed this thread and having looked at the picture again another possibility comes to mind. Have you considered magnesium deficiency?
If you google you will see exactly the symptoms: green veins and discoloration in between. You state that you use a fairly concentrated fertilizer but does it contain trace elements? Have you changed the substrate? Have you changed light exposure?
Soil chemistry is a very complex subject and I am not a chemist. But reading that you frequently use a (diluted) concentrated fertilizer there may be a buildup of some components which prevent the uptake of others? Just a thought.
Uli 

Quote from: David Pilling on November 14, 2024, 03:45:44 PMWhat would make a nursery able to avoid a source that you could not.

Quote from: CG100 on November 14, 2024, 11:44:26 PMThat said, plants with supposed virus infections are very far from common in enthusiasts' collections.

Quote from: Uli on November 15, 2024, 12:04:57 AMHave you considered magnesium deficiency?

Quote from: Uli on November 15, 2024, 12:04:57 AMYou state that you use a fairly concentrated fertilizer but does it contain trace elements? Have you changed the substrate? Have you changed light exposure?

The plants were outside on a porch during the Spring, Summer, and Autumn and are inside under lights now. I first noticed the condition during the summer. If it was a virus, it could have been spread to the plants by insects while outside, but I check my plants regularly for pests and I never noticed any on these Griffinia.  I don't have this condition on any of my other species Griffinia, nor any other of my other plants.

I checked the labels of the fertilizers I use and they all contain magnesium, as well as copper, iron, manganese, zinc, and one contains even boron and molybdenum. But, it would probably be a good idea to flush the potting mix with plain water to clear it of any residual accumulation of salts, etc.  I have changed the substrate recently and the light exposure has been changed by bringing the plants inside for the winter.  I will research the magnesium possibility in greater detail.

I'm also a member of the Gesneriad Society and I have read recently about extensive personal collections of Gesneriads being infected with Impatiens Necrotic Spot Virus (INSV), requiring the destruction of all of the plants and starting over from the beginning.  Many Gesneriad growers raise their plants indoors under lights and they are going to great lengths to prevent thrips on their plants, because thrips spread the INSV. As well as using systemic insecticides, some are even purchasing predatory mites which they release on their indoor collections in their houses and garages. Better to have beneficial mites in your dwelling than thrips!

I will research trace nutrients more, be more conscientious about fertilizing, watering, and lighting. I am going to let the soil dry out a bit in the hope that the leaves will dry and I'll remove them and give the bulbs a rest period.  My best guess is that these plants don't have a virus, but rather have other special needs that I have not discovered yet. In the meantime, I've removed them from the rest of the plants and they are now in a semi-quarantined state while I see if I can resolve this issue.

Many thanks to Carl, David, and Uli for your comments and suggestions. I appreciate it.

I searched the web for magnesium deficiency in plants and many of the photos of houseplants on the web had images that are similar to my situation. The Royal Horticultural Society had some good advice to provide my plants with a quick and easy treatment for magnesium deficiency using Epsom salts. 

https://www.rhs.org.uk/prevention-protection/nutrient-deficiencies

"Over-use of high-potassium fertilisers (such as tomato feed) can cause magnesium deficiency, as plants take up potassium in preference to magnesium." (One of the fertilizers I use is Miracle-Gro Tomato Plant Food 20-20-20 with micro nutrients.)

"Remedy: In the short term, apply Epsom salts as a foliar feed in summer. Dilute the salts at a rate of 20g of Epsom salts per litre of water (1/3oz per pint) plus a few drops of liquid detergent. Apply two or three times at fortnightly intervals, spraying in dull weather to avoid leaf scorch. In the long term apply to the soil around the roots either Dolomite limestone (calcium-magnesium carbonate) at 100g per sq m (4oz per sq yd) or Epsom salts (magnesium sulphate) at 30g per sq m (1oz per sq yd). Dolomite limestone will make the soil more alkaline, so should not be used around ericaceous (acid-loving) plants such as rhododendrons or camellias, or where the soil is already alkaline."

I'll purchase some Epson salts and mix a dilute solution for the next few waterings to see if it helps.  I may also try it as a foliar spray.  Wish me luck.

A watering with epsom salts can do no harm, except that you'll have to buy 168-years'-supply in one go, I suspect.

I thought that the ancient tale about watering/spraying in bright sun had finally been abandoned, but obviously not. If it were true, plants would be laid waste after rain if the sun came out - something very common in the UK at least. I have always thought it was totally illogical and never worried.

As for predatory invertebrates - they need prey to eat. No prey, no predators. No predator completely eliminates prey in real life either.

Going back to my childhood, growing vegetables with my father from the age of not much over 0, I must have grown many tens, if not hundreds, of thousands of plants, many very long term - some here now I know for certain are way over 20 years old and some are probably over 50. Just the Amaryllis comes to mind as likely to be infected with virus.

If I were a commercial grower of sugar beet, or potatoes, or a few other crops that routinely suffer from virus problems...........................................

Fertilisers - I suspect that I am not massively different to many/most in the UK - I use around half strength 15-15-30 mostly, and then either 12.5-25-25 or an even lower N as bulbs start to go dormant.
One popular "universal" fertiliser here in the UK is Miracle-Gro which boasts massive growth and profuse flowers - it is high in both N and K (although there are other formulations under the same brand).

I do not recall ever seeing a soluble fertiliser formulation that did not include numerous trace elements.

Quote from: Bern on November 15, 2024, 11:51:20 AMWish me luck.

Good luck.

Virus would be a good research project for the PBS to fund - examine someone's bulb collection and report back on what has virus and not.

Lilies are a bulb that has virus problems - some are tough enough to not show any symptoms others succumb easily. Propagation by seed does not transmit the virus, then there are ways of propagating them without propagating any virus.

"Virus Yellows disease, a complex of three viruses transmitted by aphids, reduces the photosynthetic capacity of sugar beet leaves, which in turn reduces the sugar content and yield of this crop. Historically, Virus Yellows has been controlled by neonicotinoid seed treatments."

and bee lovers dislike neonicotinoids.

David

I'm sure the neonicotinoids were used to control aphid populations which transmit the virus.