[pbs] Virus
John Grimshaw
j.grimshaw at virgin.net
Tue Nov 21 02:44:08 EST 2006
John Bryan wrote in the context of Hippeastrum:
To say that all stocks are infected I feel is not only not true but unfair.
Growers in the
> Netherlands are very conscious of the need to sell only the best
> possible stock.
I think is should not go uncommented on, as in my experience the Dutch
phytosanitary inspectors have a fairly relaxed approach to viral disease
(and more serious issues, like Sudden Oak Death fungus in Rhododendron and
Viburnum). I am not familiar with the situation in Hippeastrum, but many ARE
virused and MOST carry Stagonospora curtisii (which does not affect them too
badly but can be devastating to other amaryllids). This is just accepted as
the norm in the trade. I was once talking to Floris Barnhoorn from Hadeco at
his stand at the Hortifair trade show in Holland, where the display bulbs
had been grown in South Africa and shipped in a near flowering-state to
Holland. As we talked I saw the obvious signs of Stagonospora on some of the
bulbs, and mentioned it with a comment on phytosanitary matters: he just
said 'Shh, you weren't suposed to see that.'
I would say that the vast majority of commercially-grown Narcissus are
visibly virus-infected (many Dutch-sold daffs are grown in England), as are
stocks from many other genera. The bulb growers know this very well and know
also that in most cases the virus has limited effect on the bulb -
especially when grown in ideal, heavily fertilised conditions... I think it
is true to say that stocks with really debilitating viruses are destroyed,
but John Bryan's words 'the best possible stock' cover a lot of sins!
John Grimshaw
Dr John M. Grimshaw
Sycamore Cottage
Colesbourne
Nr Cheltenham
Gloucestershire GL53 9NP
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