Ferraria - Rust?

[CG100]

Does anyone grow a few pots/different species of Ferraria?

I have one pot of F. crispa (around 6 plants) which looks to have rust, based purely on appearance - slight yellowing and drying-out of the leaves in patches, which slowly spread. Oddly, a second pot of the same species, a few feet away, seems as though it may have early signs. Nothing so far on any of the other 3? 4? species that I have.

I first thought that I may have over-watered, but that looks all but impossible now.

I did spray once, with a copper fungicide, but it didn't appear to make any difference, but I was far from thorough.

Thoughts, anyone?

[Uli]

Pictures ?

[CG100]

My question was really if rust or anything similar is common on any Ferraria.

So far as I recall, the only time that I have ever seen rust before has been on wild grasses; I don't think that i have ever seen it even on roses. And yet two plants near certainly have it this winter.

[Martin Bohnet]

As someone cultivating Ferraria considerably too cold and too wet in the harsher parts of winter, I've never seen "rust" on them, as in localized dryish discoloration and fungal growth - I'm battling more of a botrytis-type of fungus - things wilt and get  mushy.

[CG100]

The greenhouse leaks a bit here, fortunatley, just in the corners, so RH is definitely too high this autumn/winter - it has barely stopped raining for weeks upon end here.

It just struck me as odd that two Ferraria had shown what I am sure is rust.

I did buy some systemic fungicide a week or so back........

The plants are kept at 5C minimum and I was surprised to see what must surely be scorch (too low a temp.) on Pauridia capensis - the leaf tip blackend to 3-4mm. 

One batch of over-wintering Haemanthus humilis seedlings also have very dark leaves, which looks like cold-damage, although the leaves are still firm, and the 2-3-4 other clones, all larger, look perfectly OK.

[illahe]

I have been growing Ferraria in Western Oregon's damp, cool winters for some years now and noticed something similar to what you describe. The growing tips of the first leaves to emerge almost always get hit with some sort of a fungal blight. It does look like rust, but also black mold and botrytis as well,  I have yet to send a sample in for a lab diagnosis. I do have a theory since it's always the first leaves to emerge, which for me here is often in October, followed shortly by Novembers wet and cold. I don't heat the bulb house at all so the South African collection is growing very much at the margins of cold survivability. I think the tips of the newest leaves are getting dieback and then getting a host of fungal pathogens decomposing them, rust, botrytis, etc. Often times they will grow out of it, and the older foliage is not affected as much as the tips. I have tried several different fungicides, even spraying as the new leaves emerge in the October to be pre-emtive about it and it seems to have no effect. Which leads me to believe it's actually a tip die back of the leaves that is then succumbing to a fungal pathogen and not the fungal pathogen as the root cause. Have a look at the picture attached and let me know if yours look similar?

I think the only "cure" would be a warmer, more controlled environment to harden the foliage off a bit better, when trying to grow Ferraria in cold, damp winter conditions. For now I cut the tips off after and live with some raggedly looking plants in hopes that I will get flowers. What is interesting is that I have only ever seen this on Ferraria and Watsonia,Gladiolus, Moraea, Babiana, Freesia and other marginally hardy South African winter growers in the same house and conditions are unaffected. I can't find much research on Ferraria pathogens, must not be an economically viable area of study.

Mark

[CG100]

Thanks Mark @illahe

Yes broadly similar, your foliage looks slightly lusher, which is probably down to numerous reasons of culture here v. with you, but it also means that the infected leaves here are generally drier throughout, from the first hint of a problem to the whole leaf suffering.

I have sprayed the affected plants a couple of time with systemic fungicide, but suspect that it is too late to produce much/obvious of an effect this growing season.

I have changed things around this winter and suspect that they were around two degrees warmer, as a minimum, last winter, so maybe the clue is that. But we have had/are having the mother of all wet winters so far too; irrespective of any leak, ambient humidity must have been through the roof for long periods.