Cyrtanthus seedling problem

Hans-Werner Hammen
Thu, 05 May 2005 15:24:07 PDT
I faced a similar problem when I tried to raise the common Cyrtanthus, the 
former Vallota purpurea from seeds, although I never used the floating 
method, but sowed into coarse sand covered  with a thin layer of fine sand. 
The whole first leaf suddenly withered when it hat jiust reached 1-3 cm in 
length - but note, no leaf base rot / damping off was visible.

I can not offer a clear explanation. BUT From my other sowing experiments, 
perforned on a large scale with 4ploid hippeastrums I noticed something what 
I speculate to be a mild form of this disorder. Some of these seedlings 
suddenly develop a strong depigmentation of the leaf edges and  sometimes 
the whole leaf becomes whitish. But very few seedlings are so seriously 
weakened that they die.

When the selected strongest seedlings, repotted into coco peat begin to 
exhibit very rapid growth these signs of disorder reappear in a very mild 
form, although clearly visible to me.
To make it short now, I speculate that all the seedlings contain a virus 
which is normally latent. As I read that virus is normally not transmitted 
from seeds I must consider an infection in a very early stage of the 
development. This would explain the sudden manifestation of symptoms.

I have tried the flotation method, too and found it very tedious/cumbersome. 
I prefer to sow my 100s of amarylli(d)'s seeds directly into coco peat now, 
putting them with blunted tweezers into preformed drill lines with a ruler, 
obtaining a germination rate of better than 80%.

Careful attention must be paid not to let the sciarid flies (fungus gnats) 
get access. If seedlings  die they should be carefully inspected in order to 
differentiate between fungus gnats (the leaves are eaten up under the soil 
surface, or a hole has been eaten into the basal plate of the tiny bulb - 
and the bulb scale mite, Steneotarsonemus laticeps ( the leaf is deformed 
and one or both edges are red and this discoloration begins in the bulb). 
This mite is very easily transmitted, so easily that it seems as if it could 
"fly over a certain distance".

However, as regards to Cyrtanthus, now I would try to sow out directly into 
a solid substrate. If you have a lot of seeds from a common cultivar, sow on 
the largest scale you can afford. You WILL finally obtain some surviving 
seedlings, might they contain a virus or not.

I consider that far far more plants are latent-ly infested with virus than 
we know; I am pessimistic in this aspect. But even If I had to consider that 
my whole collection might be infested I shall never get discouraged by that. 
(But however, needless to say that I discard hippeastrums with clear signs 
of ugly mosaic virus as quick as possible, in their whole pot)


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