Re: Mosaic Virus in AG

cc: to Pumpkins
Thanks for your reply. It will help me in looking for answers. I will
send some info that is not in my virus books. 

COMPUTRESE@aol.com wrote:
> 
> Harold:
> 
> Thanks for your response.
> 
> None of the popular AG books (I have them all) cover the subjuct with concrete
> facts. The only thing they say is Mosaic virus =doomsday. They are correct,
> but I need to know more about the virus and it's MO.
>
  There is never a cure for viruses in any organism, except some of the
AIDS mixtures. I guess by MO, you mean that info such as pollen borne
etc would help guide you pollination and other practices.   
  The effect of a given virus on yields in small fruit is variable from
no effect to no crop. A strawberry technician at a University breeding
program showed me some seedling strawberries that were barely able to
stay alive following virus infection and I have had the same in my virus
house. Those seedings never make it to the public. In breeding giant
pumpkins or any breeding program that concentrates only on one goal,
there is the risk of developing cultivars which are highly sensitive to
one or more viruses. Sometimes a cultivar is virus sensitive, but no 
vectors (aphids, nematodes) are present or the plant is distasteful to
the vector sometimes due to hairy leaves.
 
> Mosaic virus wiped out my entire pepo pumpkin patch last year. Curious to know
> why the virus began there, that is could it have been in the seeds?
> 
> Does the virus corrupt the genetics of the plant and its fruit, thereby lying
> dormant in the seed? When the seed is planted, the virus erupts again? This is
> the scourge of the cucurbits!
> 
> Barb
  Temperate viruses are known in bacteria which cause mutations by
inserting themselves within the "chromosome". In corn we have mobile
elements which insert many places and cause disruption (mutation) of the
affected genes. These "jumping genes" are not viruses but act very much
as a virus in that respect. I am not aware of any pumpkin virus that
causes mutations.
  Yes, to our eyes seed borne viruses are dormant when the seed is
dormant. I don't know whether we know anything about the location and
status of dormant viruses in seed. 
  My only experience with plant viruses is in sweetpotato, strawberry,
blackberry, and raspberry. I have spent some time in most of the main
labs doing work with those 10 years ago. 
  The main way we detect viruses is to graft a leaf onto a species which
is highly sensitive to the virus. We also rub sap from the plant onto
leaf of a certain lambsquarter. The fastest way is to use antibodies if
available. 
  You said virus infected plants are useless. Therefore, I would kill
infected plants when they are found. That is standard practice on farms
which grow small fruit plants for the public. Some viruses are so easily
transmitted that walking in a field can transfer the virus when you rub
against the plants. Some potato viruses are so easily transmitted that
workers try to stay out of the screenhouses. Water valves are located
outside the buildings.
  
  If no one has a web page on pumpkin viruses, I will start one. If I
start one, I would depend upon growers for their observations. We could
begin with Barb, on close discussion we might decide her problem was not
viruses. Since I have no plans to grow record sized AG, it would be OK
for me to have viruses in my garden and virus house. Folks could send me
the materials and I could run tests. For example, folks have sent me
questionable sweetpotato vines and I have tested them by grafting to
Brazilian Morning Glory which is a good indicator plant for Iopemoa
viruses. 

-- 
Harold Eddleman Ph.D. Microbiologist.       i*@disknet.com 
Location: Palmyra IN USA; 36 kilometers west of Louisville, Kentucky
http://www.disknet.com/indiana_biolab



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