twin scaling quandry
Mon, 08 Dec 2003 22:43:01 PST
In a message dated 08-Dec-03 5:36:18 PM Pacific Standard Time, writes:

Michael ~

> I have a question about twin scaling Hippeastrum.  After following a 
> combined 
> procedure by RHS and IBS, using Cleary's 3336F on the scales, in sterilized 
> perlite, I'm noticing an even pink coloration on the scales.  I think, hmmm, 
> damnable Stagonospora... yet I used Bonomyl (Benlate sub) for soaking the 
> bulb 
> prior to storage, Bleach (1:10) prior to cuttage, and 3336F for the final 
> soak, 
> alcohol rinsed surfaces and sterile razors.  Do Hippeastrum show red or pink 
> as a form or oxidation to damaged cells or is my culture simply 
> contaminated? 
> Any remedies?
I've not TS-ed hippeastrum, but have done a considerable amount with 
daffodils (Narcissus) which, as tunicate bulbs, respond the same.

I'm not certain what you describe as "an even pink coloration on the scales" 
really is.  Is it clearly a fungus?  I know that many bulbs of Hipp. are 
plagued with stagonospora.  The only cure I've seen for it is the hot water 
treatment procedure.

It sounds from your description that you've done everything right.  I'd make 
two observations, however.  Benomyl (and similar compounds) do not eradicate 
these fungi, they only suppress them.  Depending on the conditions during 
incubation determines whether the suppression will hold or break down.  One point 
where this process often fails for many people is that the incubation medium 
becomes too wet.  I usually take the sections of the scaled bulb out of the 
fungicide soak and drain them on paper toweling until dry.  They're then placed 
into Baggies with some barely damp medium (I usually use peat moss).  When I say 
"barely damp" that is exactly what it has to be.  The object of the medium is 
to assist in maintaining the humidity level.  You're probably only going to 
be raising it around 20-30% -- it doesn't take much additional moisture to do 
that.  And the other problem is that, as living tissue, these sections expire 
moisture.  That moisture collects in the sealed Baggie.  One has to check the 
moisture content every two or three weeks and replace the medium or leave the 
Baggie open for some time to dry out the medium and contents.  With strict 
attention to the moisture in the incubation process, this whole thing is 
relatively easy to do and usually quite successful.  I have, however, gone to larger 
sections and no longer work with true twin-scales.  They are so small that it 
just introduces another variable that has to be monitored and controlled.

Dave Karnstedt
Cascade Daffodils
P. O. Box 237
Silverton, Oregon  97381-02378
Cool Mediterranean climate of wet winters and hot dry summers; USDA Zone 7-8

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