Virus Confirmation

COMPUTRESE@aol.com wrote:
> 
> Harold:
> 

> My AG plant is growing and blooming, also is sprouting new growth in
> profusion everywhere I pruned off old, dying leaves and stems. The new leaf
> growth does not have the mosaic patterns. Isn't that remarkable? Perhaps the
> virus is localized? Odd but very nice.
> 
> In case you're wondering, my pumpkin is 211 total inches, or about 203 lb.
>
  I am not a plant virologist in the sense of working with them
full-time, but I have visited many labs which primarily work on plant
viruses and I have done considerable work here at Indiana Biolab. 
  My work is with some strawberry viruses which are difficult to
identify or confirm. Dr. Converse, told me he once tested a plant
exhaustively and found it was virus-free. Sadly, it died of virus a few
months later. It was infected when he tested it, but the correct
indicator plants did not show it. 
  Pumpkin viruses should be much easier to confirm. There are two main
ways to show a virus in your prize plant:
1) sap test
2) grafting
both require one or more different species of indicator plants. Certain
lambsquarters and cucumber (National Pickling cultivar) are most often
used. If you can get National Pickling, I suggest it. I don't have any
National Pickling seeds now, but When I have them I start a few seeds in
pots each week so that I have them on hand. 
  We grind the pumpkin leaf in phosphate buffer with smashed glass or
grinding powder. Then we smear that mix on the seed leaves of the
National Pickling and in days we see yellow spots on the seed leaves.
The glass powder or carborunum (sp) scratches the upper surface of the
National Pickling seed leaves and the virus particles get into the cells
and cause a focus of infection. various colors and shapes of lesion
occur for various viruses on various hosts. 
  Pumpkin leaves are juicy. I would not worry about Phosphage buffer.
just grind or pound the suspected leaves with sand or pounded glass.
Protect your eyes from flying glass. Perhaps you can fold a bit of
pumpkin leaf between plastic film or aluminum foil. You only need a drop
sized amount.  Remember you only need a cubic millimeter (pin head)
sized piece of glass. I use a laboratory mortar, but you may not have
one. 
  This sounds so easy, I urge anyone having suspected virus to try it. I
have not tried this method but will when I get some National Pickling. I
will try it on some weeds having mosaic leaves. If you don't have
National Pickling use what ever cucurbit seeds you have. If you get
spots that is positive, if you don't get spots, you might have gotten
spots with a different indicator plant. 
  I will try to get this all on a web page, but I keep forgetting.
-- 
Harold Eddleman Ph.D. Microbiologist.       i*@disknet.com 
Location: Palmyra IN USA; 36 kilometers west of Louisville, Kentucky
http://www.disknet.com/indiana_biolab/v.htm



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