I'm nearly certain that the 10 new Cabernet Sauvignon vines I planted
this spring are infected with grapevine leafroll virus (GLV). By
mid-summer the leaves started to exhibit the classic inter-veinal
reddening and downard rolling of leaf margins. From what little I've
read, it seems that the virus is typically propagated through cuttings
and secondary vectors not spread from plant to plant by contact or
seed.

Anyone have experience with this? I purchased these vines from Double
A vineyards in NY. Should I ask for replacement vines?

RD

Are you finding that the ripening is very delayed with these vines
(sugars low and colour not getting darker)?
Joe
RD wrote:
> I'm nearly certain that the 10 new Cabernet Sauvignon vines I planted
> this spring are infected with grapevine leafroll virus (GLV). By
> mid-summer the leaves started to exhibit the classic inter-veinal
> reddening and downard rolling of leaf margins. From what little I've
> read, it seems that the virus is typically propagated through cuttings
> and secondary vectors not spread from plant to plant by contact or
> seed.
>
> Anyone have experience with this? I purchased these vines from Double
> A vineyards in NY. Should I ask for replacement vines?
>
> RD

Joe,

These vines were just planted this year so no fruit.

RD

Do you have dry soil??? Did the plants get plenty of water or did you
try and make the vines suffer?

Bob


RD wrote:
> I'm nearly certain that the 10 new Cabernet Sauvignon vines I planted
> this spring are infected with grapevine leafroll virus (GLV). By
> mid-summer the leaves started to exhibit the classic inter-veinal
> reddening and downard rolling of leaf margins. From what little I've
> read, it seems that the virus is typically propagated through cuttings
> and secondary vectors not spread from plant to plant by contact or
> seed.
>
> Anyone have experience with this? I purchased these vines from Double
> A vineyards in NY. Should I ask for replacement vines?
>
> RD

> Do you have dry soil??? Did the plants get plenty of water or did you
> try and make the vines suffer?

There is no need to make vines suffer the first year they are planted.
They need strong root growth at this point. Plenty of rain here this
summer but the vines were watered during dry spells.

"Vine symptoms are not a reliable indicator of the presence of leafroll
virus because other factors may lead to similar symptoms"

This quote is from
http://winegrapes.tamu.edu/grow/diseases/leafroll.shtml

Bob

RD wrote:
> > Do you have dry soil??? Did the plants get plenty of water or did you
> > try and make the vines suffer?
>
> There is no need to make vines suffer the first year they are planted.
> They need strong root growth at this point. Plenty of rain here this
> summer but the vines were watered during dry spells.

"Leafroll causes a degeneration of phloem tissue in young shoots,
leaves, petioles and rachis. Symptoms similar to that of leafroll can
be brought about by actions that damaged the phloem, for example
mechanical damage to the trunk, breaking of shoots, poor graft unions,
girdling and the pinching effect of ropes. Low temperatures, as well as
leafhoppers, may cause discoloration, which can be confused with
leafroll. All red discoloration of vineyards should therefore not
inadvertently be attributed to leafroll."

Bob

wrote:
> "Vine symptoms are not a reliable indicator of the presence of leafroll
> virus because other factors may lead to similar symptoms"
>
> This quote is from
> http://winegrapes.tamu.edu/grow/diseases/leafroll.shtml
>
> Bob
>
> RD wrote:
> > > Do you have dry soil??? Did the plants get plenty of water or did you
> > > try and make the vines suffer?
> >
> > There is no need to make vines suffer the first year they are planted.
> > They need strong root growth at this point. Plenty of rain here this
> > summer but the vines were watered during dry spells.

> Low temperatures, as well as
> leafhoppers, may cause discoloration, which can be confused with
> leafroll. All red discoloration of vineyards should therefore not
> inadvertently be attributed to leafroll."
>
> Bob

And so where are you growing the vines - New York? Isn't Cab normally
considered to like warmer climates, and are you therefore getting low
temperatures (or at least the grapevines think so) now?

Rob

Growing in SE Pennsylvania. Cab does grow here successfully at several
local wineries. We have hot summers - it's the potential winter kill
that could be a problem.

I appreciate that other causes could produce similar symptoms to those
of Leaf roll but I believe I have eliminated most. This article from
the WSU extension is very helpful with good pictures for anyone
interested.

http://www.fruit.wsu.edu/Grapeweb/vol16-3-2006.pdf

RD

The only ways to know for sure if you have a plant virus are to send a
sample to a lab or buy a test kit for the suspected virus.

Here's a lab that offers several test kits for GLF so you could call
them for advice. Since the kits can be somewhat expensive, you may want
to ask them if they know someone who might sell a test strip of two
from their kit or a distributor that might sell in small quantities. We
get other products from a distributor here in Colorado that also sells
the Agdia virus test kits (mostly for greenhouse crops) and he may be
someone to contact. Let me know if you want his name and number.


http://www.agdia.com/

Better yet, Penn State probably has a plant diagnostic lab that could
help you. Check with your county extension office before trying the
private lab I suggested.