Was Edible Bulbs - Allium, now crop rotation
Peter Taggart (Sun, 06 Nov 2011 13:37:41 PST)

I have experimented with reticulata Iris a great deal. I wash the (clay)
pots every year, and dust with Bordeaux Mixture (sulfur) when repotting and
also use dolomitic lime. I discard the spent potting compost - not near my
frames!
I do grow and flower them from seed,
the best controls I have found for Ink Spot is good hygiene and stable
growing conditions.

I find the best way to introduce Ink spot is to stress the plants in the
last stage of growth and early dormancy with erratic temperatures and
moisture levels. This fits with Rolands advice.

It is a lottery as to whether an individual pot will have suffered from the
disease but I can normally produce clean pots of all the commercial
varieties I have ever managed to obtain, as well as the wild forms.
I am skeptical that cutting the bulbs would remove the disease, Brian
Mathew in "The Iris" regards an infected bulb as incurable. However
infected bulbs will yield pristine bulbils which will grow on into healthy
bulbs.
I know there are others here who know more about fungal infections than I,
but I do believe to discard the sclerota, if that is the right term, is not
to remove an infection.
Peter (UK)

On Sun, Nov 6, 2011 at 8:32 PM, Rodger Whitlock <totototo@telus.net> wrote:

If you are raising reticulata irises from seed (and hence have absolutely
clean
plants), it would be a advisable to completely refrain from bringing
commercial
forms into your garden.

If commercial reticulata irises are irresistible but you don't want to
introduce ink spot into your garden, you may wish to try eliminating it
from
newly purchased stock. Peel the tunics off the bulbs. Carefully examine
each
bulb and using a new single-edged razor blade, cut out any lesions you
find.Dust
the wounds with sulfur. Plant the bulbs in new soil in a clean pot and
grow on
in the normal way.

Be careful that the tunics you remove, and slivers of bulb you have cut
out,
the razor blade you use, and the soil you have grown them in (for just one
year) all go into the garbage, not the compost. Clean the pots with liquid
chlorine bleach before re-use.