Wendy Silverman
Master’s Candidate At
Penn State
Extension Education
From June 19-22, 53 State
Horticulture Association of
Pennsylvania (SHAP) mem
bers traveled to Nova Scotia
for an orchard tour of the An
napolis Valley. Associate Pro
fessor of Pomology Dr. George
Greene, and Executive Secre
tary of SHAP Maureen Irvin
organized this trip. Our Nova
Scotia hosts were Bill Craig of
the Nova Scotia Department of
Agriculture and Charlie Em
bree of Agriculture and Agri-
Food Canada. Our days were
packed with events from
orchard tours to exploring
working seaports.
We flew from Harrisburg to
Allentown and then to Toronto
on a 40-passenger commuter
plane, and from Toronto to
Halifax on a Boeing 337. Our
Saturday dinner was at Peggy’s
Cove, a community of about 50
residents, which features an ex
cellent restaurant, a few gift
shops, and a lighthouse that
also is a post office in the sum
mer season. Peggy’s Cove has
a very narrow port where only
small boats would dare to en
ter. The cove has a rocky land
scape, which gives the place
mystical characteristics. In
September 1998, a Swiss Air
flight tragically went down 10
miles off the coast of Peggy’s
Cove. Sadly, several Pennsyl
vania residents were on board
On Sunday we visited Ma
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State Hort. Members Tour Annapolis Valley
hone Bay and Lunenburg. The
entrance signs to Mahone Bay
read, “We love the beauty
around us and welcome you to
share it.” There are three
churches standing side by side
when you enter the town. The
churches are a well-known in
ternational landmark. Mahone
Bay is a small town and very
quiet on Sunday morning be
cause most businesses do not
open until noon. I guess the
majority of the store owners
must have been at church that
morning.
Lunenburg was formed as a
shipbuilding and seafaring
town in 1753. It was a much
larger port than Mahone Bay,
with several restaurants, gift
stores, art studios, a museum,
and boat tours. This town was
known for building famous
wooden ships such as the Blue
nose, HMS Bounty, HMS
Rose, Bluenose 11, and the Pic
ton Castle.
From there we headed off to
the Annapolis Valley, the or
chard belt of Nova Scotia. The:
Annapolis Valley borders the:
Bay of Fundy, where the high
est tides in the world occur. We
visited five different orchards
and the Atlantic Food and Hor
ticulture Research Centre in
Kentville. Several production
issues were discussed on these
tours. Emphasis was placed on
how to increase tree vigor on
dwarfing rootstocks, chemical
thinners, irrigation, and or
chard disease and pest prob
lems.
Grower and Marketer, Lancaster Farming, Saturday, December 11, 1999—Page
Increasing Tree Fruit Vigor
On Dwarfing Rootstocks
The most common problen
Nova Scotia orchards must
overcome is not getting enough
tree vigor with dwarfing root
stocks. In Pennsylvania we
have the opposite problem, too
much vigor. Trees in Nova
Scotia have low vigor because
of climate. Additionally, root
stock selection, soil type, or
chard system, and overcrop
ping can further reduce vigor.
Dwarfing rootstocks are
used in high density plantings
in efforts to achieve high yields
early in the life of the orchard.
The two most common root
stocks being used in Nova Sco
tia are M. 9 and M. 26. Many
trees on these rootstocks have
not filled their space even after
six to seven years.
The soils are very diverse in
Nova Scotia. Soil types can
change even in the same tree
row. If an orchard or a group of
trees in an orchard is exhibiting
poor performance, soil is often
the problem. Problems include
hardpan, inadequate nutrients,
and poor site preparation, espe
cially in replant sites.
Keith Fuller, a visiting soil
scientist from South Africa,
suggests that growers should
begin preparing the site three to
five years before the intended
planting date. Apple produc
tion began in the Annapolis
Valley in 1633; therefore, us
ing replant sites is a common
occurrence. Fuller suggests
«
55 & 85 GALLON REAR MOUNT SPRAYERS
that most old orchard soils
need fumigation to control re
plant diseases.
Climate in general is much
cooler in Nova Scotia, al
though the winter lows are
similar to those in Pennsylva
nia. They have entered their
third consecutive drought year,
which has contributed to a con
siderable amount of tree stress.
There are several orchard
systems in use in high-density
plantings. The various systems
we saw in the Annapolis Val
ley were modified slender
spindle; vertical axe; V-trellis,
using both V- and Y-style
planting; and a high density
planting using unsupported
semi-dwarf rootstocks.
Of the supported methods,
the vertical axe system was the
most favored by the orchardists
we visited. They liked it be
cause they were able to achieve
an ideal height of 12 feet and
maximize their canopy vol
ume. In a vertical axe system,
there was one wire along the
top of the posts to provide ad
ditional post support.
The modified slender
spindle system is also used in
several orchards. The tree sup
ports are shorter in the modi
fied slender spindle system
than those used in the vertical
axe system; therefore, ade
quate support is not given to
the upper tree canopy. Maxi
mum canopy volume cannot be
obtained in the slender spindle
system.
The other trellis systems re
quire the branches or the whole
tree to be bent on an angle,
which reduces vigor. In Nova
Scotia, these systems cause too
much vigor reduction and the
trees look stunted. Pennsylva
nia uses systems like the V
trellis to reduce tree vigor to a
desirable level.
One method that looked
promising for Nova Scotia was
planting larger, free-standing
rootstocks close together. This
was accomplished at a root
stock trial by Charlie Embree,
and J.P. Priv’e in Kentville. Vi
gor was contained by over
crowding the trees to limit root
growth by using a pruning
method that would limit tree
vigor and by using spur varie
ties that are less precocious. A
freestanding tree takes longer
to crop, which limits returns.
One other factor that dwarfs
or “runts out” a young tree is
overcropping. When a tree has
too many fruits, the tree will
apply much of its energy to
fruit development and not tree
growth. One way to control
this problem is by removing all
fruit during its early years.
Since it takes too long to hand
thin, many orchards are now
using chemical thinners. Al
though thinning solves the
problem of high loss of vigor in
young trees, removing the fruit
defeats the purpose of using a
high-density system, which is
to increase early production.
Chemical Thinners
Chemical thinners
were discussed sever
al times on the tour.
This was emphasized
because, like Penn
sylvania, Nova Scotia
has a high consumer
demand for large
colorful apples. To
achieve this demand,
only one apple can
grow per cluster of
blossoms and some
times even this pro
duces too many ap
ples.
from
191
Nova Scotia or
chardists are looking
into chemical thinners
to reduce the number
of apples per tree be
cause hand thinning
would not be eco
nomical.
The most difficult
types of trees to con
trol fruiting are bien
nial bearing trees.
This is when vigorous
varieties produce too
many fruit one year,
and hardly any fruit
the following year.
Triploid verities, or
trees that contain
three copies of their
genes, are also heavy
fruit bearers. Graven
stien, a popular culti
var in Nova Scotia is a
triploid tree.
As mentioned ear
lier, Nova Scotia is
also looking at chemi
cal thinners to de-fruit
young trees so .hey
will not “runt out”
from overcropping.
There are several
chemical thinners on
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