Agriculture Reference
In-Depth Information
Table
.
Relative susceptibility of various apple rootstocks to selected diseases and
insects
a
Crown
Fire
Apple
Powdery
Latent
Woolly
Rootstock
rot
blight
scab
mildew
viruses
aphid
'A.'
MS
VS
MR
MS
T
S
'B.'
VR
S
M
MS
T
S
'B.'
MR
M
M
S
T
MS
'B.'
MS
S
M
MS
NT
S
'M.'
MR
MR
M
MR
T
S
'M.'
R
MR
M
M
T
S
'M.'
MR
R
M
MR
T
S
'M.'
R
S
M
MR
T
S
'M.'
R
M
M
MR
T
S
'M. '
MS
S
M
MR
MS
S
'M.'
R
MS
M
MR
MS
S
'MM.'
S
R
'MM. '
S
M M M T
R
'MM.'
M MM S
T
R
'Novole'
R
R
R
MR
S
MR
'O.
'
R
MS
M
MR
S
VS
'P.
'
MR
MS
NT
MR
NT
MS
'P.
'
R
MS
NT
MR
NT
MS
'P.
'
R
MR
NT
MR
NT
S
'P.
'
R
MS
NT
MR
NT
MS
'Robusta
'
R R R
R M
R
Based largely on Cummins and Aldwinkle (
). Rootstock abbreviations as in
Table ..
a
Rating system: VS, very susceptible; S, susceptible; MS, moderately susceptible;
M, intermediate; MR, moderately resistant; R, resistant; VR, very resistant; NT, not
tested; T, tolerant.
From Ferree and Carlson (). Reprinted by permission of John Wiley & Sons Inc.
The most important insect pest of rootstocks is the woolly apple aphid
(
Eriosoma lanigerum
; see Chapter
), which can stop tree growth in
warm-climate production areas. The 'M.I' and 'MM.' series of rootstocks
were bred specifically for resistance to this pest.
The relative resistances of the different rootstocks to these pests and diseases
are given in Tables
,p.
.
and
.
. These ratings must be treated with caution.
Quamme
et al.
(
' is among the most resistant of
rootstocks to
Phytophthora cactorum
, in agreement with the results of Cummins
and Aldwinkle (
) concluded that 'M.
), Sewell and Wilson (
) and general field experience.
However, whereas Sewell and Wilson (
) found 'M.
' and 'MM.
'tobe
resistant and 'M.
' to be susceptible, Ferree and Carlson (
) classed 'M.
'
as moderately resistant and 'M.
' and 'MM.
' as moderately susceptible;
and Quamme
et al.
(
) classed 'M.
' as moderately susceptible, 'M.
'as
