Re: Iris Scorch

In a message dated 5/1/2006 4:00:25 P.M. Central Daylight Time,  
kmckeem@direcway.com writes:

Hello,
I  follow the Iris forum, but have never participated in it before.
I am seek  any information about Iris Scorch, and the treatment for it.  
Should you  dig them up and destroy them or let them be and see what happens.  
We  have been extremely dry for the last 2 years where I live here in  
Kansas.  In January we had average temps in the 60's.  Then in Feb.,  it dropped 
into the teens.  I am wondering if the dry, then premature  growth and then 
freezing is the cause.  
I would appreciate any advise  from you experts.
Thank you, K McKeeman 





Forgive the pun but "it is Scorching in Kansas"!  Region 18 Spring  Tour 
hosts, Hutchinson Iris Club is also reporting scorch in their Guest Iris  beds and 
are very concerned about it.  
 
Here is the feedback they have received from notable growers on the  topic:
 
 
The answer is an  emphatic and unequivocal - dig it up and get rid of it.  
Trust me, I have  vast experience with the beast.  If it is scorch, when they 
dig them up,  the roots will be shriveled; if it is frost damage, the roots will 
still be  plump. 
It is an insect  vectored disease which means it is spread by leaf hoppers 
and aphids.  If  left in place, the plants serve as a reservoir of infection.  
The insect  feeds on an infected plant and spreads it to uninfected ones.  It 
is just  like Dutch elm disease and other similar "wilt" diseases.  There are  
probably ones that are infected now that don't yet show symptoms but that will 
 as time goes on.  That is what makes it such a nasty disease.  It can  be 
spread from plants that one doesn't yet realize are infected - sort of like  the 
latency period in AIDS. 
The only way to destroy  the organism in the plant is to dig it up and heat 
it to about 110 degrees F for  at least 24 hours.  I would do this only if it 
is a plant that is of great  value.  If the plants are in lush growth, they 
stand as good a chance of  rotting during treatment as recovering.   
Each of these gardeners  has my utmost sympathy and empathy.  One of the best 
solutions is to plant  the irises among other plants as in a mixed border.  
There is nothing that  disease likes better than to have all its victims lined 
up shoulder to  shoulder. 
Mid-America Garden 
Paul Black 

and
 
 
When scorch appears in a clump it spreads from rhizome to  rhizome.  If the 
rhizomes are connected, I first immediately cut and  separate the afflicted 
rhizome from the others.  The afflicted rhizome can  be heat-treated by placing 
on concrete or asphalt in full sun and baked for a  couple of weeks.  They will 
look dead but when replanted they almost always  live.  You just lose any 
bloom that was already inside the  rhizome.
 
Jim Morris, Region 18, St. Louis, MO
 
This expert advice, others, will appear in the next MIS publication  The 
Medianite in the "Ask The Iris Vets" column. Persistent problem in the  Midwest 
especially after a winter like this-too warm, hateful cold, dry =  stress!
 

Rita  Gormley
Gormley Greenery
Cedar Hill, MO
AIS Region 18, Zone  5
http://www.gormleygreenery.com/

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