Robusta 5 failed to survive in areas where winter temperatures did
not remain below a growth-promoting minimum as long as there was risk
of severe cold. Early completion
of physiological rest allowed it to begin growth activity in mid-
winter if mid-winter temperatures were high enough, long enough.
That early growth eliminated the cold resistance that it had
accumulated during rest, so that it was susceptible to damage when
exposed to later cold. Robusta 5 is an example of the type of cold-
hardiness that may be shared by Bud 54-118.
I don't know that...it seems a possible explanation for my
Connecticut observation.
Karl Townsend did not mention the timing of the cold in Minnesota,
nor whether there is risk of warming in January or February, followed
by extreme cold.
On Feb 4, 2009, at 1:35 PM, Harold Schooley wrote:
David
Years ago I experienced something similar with Robusta 5. This
rootstock was touted to have extreme cold hardiness and I don’t
doubt that. What it did not like was warm temperatures in
midwinter followed by more cold weather. It too succumbed to cold
weather injury.
Harold Schooley
Simcoe, ON, Canada
(north shore of Lake Erie)
From: [email protected] [mailto:apple-
[email protected]] On Behalf Of David Kollas
Sent: Wednesday, February 04, 2009 10:46 AM
To: Apple-Crop
Subject: Apple-Crop: Cold-hardiness of Bud 54-118 apple rootstock
