VIGOR CONTROL
The control of shoot growth has been a central point of interest in the European and South
Tyrolean fruit growing industry in the 1990s. Growers and experts realized that only a well-
balanced tree gives a good early crop and regular high yields.
spite of all the precautionary measures. In such cases we recommend root pruning.
which:
•reduces shoot growth (by up to 55%)
•reduces fruit size (this is an advantage only with varieties producing big fruits)
•promotes fruit set in the following year
•reduces bitter pit
nutrients. Prerequisites for root cutting are:
•deep soil, free of stones
•irrigation
•vigorous growth
Root cutting should be performed in orchards with
vigorous growth, biennial bearing habits and varieties producing large fruits in the year with a
heavy crop, although generally in the year with a slight crop. A good time is probably the period
before vegetative growth begins. At that time the inhibiting effect on shoot growth and fruit size
is strongest. The later in the vegetative period root cutting is carried out, the slighter is its effect.
The distance from the trunk is more important
than the depth. For root cutting with M.9, it should be performed on both sides at a distance of
30 cm (12 inches). The cut should be about 40 cm (16 inches) deep. In the first year the
orchardist is advised to work very carefully.
reduce top growth considerably. There are several application techniques. One is painting overly
vigorous central leaders (longer than 50 cm) (19.7 inches) from the 2ndto the 4thyear.We
recommend applying the NAA solution only to the 2- or 3-year-old wood of the central leader in
a ring of 5 cm (2 inches) width. The wider the ring, the more active ingredient the wood absorbs.
Gala, Braeburn, Red Delicious and Granny Smith react, in decreasing order, rather strongly to
the application of NAA. If the central leader is very vigorous we recommend a 2% solution and
for weaker shoots 1%.
and there should be no irrigation. The disadvantages of this treatment are:The effectiveness is
not always consistent, it depends on weather conditions, vigor of the treated shoots and width of
the NAA ring. In those places where the paste is applied the central leader may lose stability and
is more likely to bend or break.
with an NAA paste. For fresh wounds use a 1% paste, for old wounds 2%. The date is not
important.
and observation is required for spraying with small doses of NAA (15-25 ml/hl) during the
summer. This can reduce the new growth by 16-30% on an average. More dards and spurs have
terminal flower buds and therefore flowering is enhanced in the following year. Depending on
the vigor of shoot growth we recommend 3-5 treatments at intervals of 10-15 days from June
drop onwards. NAA is mixable.A disadvantage is that the treatment leads to a reduction of fruit
diameter. Therefore we recommend the use of NAA only for varieties with large fruits like
Jonagold, Fuji and Granny Smith.
First of all, orchardists are encouraged to adopt
biological measures in order to slow excessive growth, for example, to apply only half the
amount of water generally required or to tolerate weeds and grass on the tree strip from mid-
summer onwards. They can absorb much excessive potassium and nitrogen.
GROUND COVER MANAGEMENT
In recent years it has become much simpler. As vegetation in the alleyway is tolerated, it is
mulched 3-5 times a year. Special attention is paid to the tree strip, which is kept weed-free
especially during the early years of an orchard (Table 6).
the trees results in slower shoot growth and lower initial yields. As soon as the trees have reached
their full volume and the bearing phase, the vegetation in the tree strip does not have any
negative effects on growth and crop.
In the IP-program, which is observed by approximately 80% of
the South Tyrolean producers, only herbicides which are absorbed by the leaves like glyphosate,
glyphosinate (Basta) and MCPA-salts are permitted. The only exception is simazine, which may
be used in the first 3 years (2 kg/ha) (1.78 lbs/acre). Glyphosate is usually applied also after
harvest before the soil freezes. The advantages of this are:
•For a good effect half the dosage is sufficient.
•The effect lasts until mid-May of the following year.
•There is little other work to be done in the period after harvest.
sometimes mixed with MCPA, will become necessary. From late summer onward we advise
tolerating the regrowth under the trees, because it absorbs a surplus of nitrogen and potassium in
the soil. This slows down growth and enhances fruit quality, especially red color promotion. In
orchards where field mice are a problem, this measure is not advisable. The weed-free strip
should not be wider than a third of the alleyway. In many bearing orchards a ground cover of
weeds throughout the planting has proved successful. In this case it is indispensable to use a
special swing arm mower which can also mow around the trees.
MATURITY AND HARVEST
For each variety and location the maturity stage is carefully monitored with the help of a number
of tests. The following parameters are used: sugar level in ºBrix, acid content in g/l, starch
conversion, penetrometer values in bar/cm2. Recommendations regarding the ideal picking time
are worked out by the technical services of the packing houses and communicated to the
growers.
although for 10 years the plastic bin (costs: US$75apiece) has been gaining steadily so that the
wooden bin will soon disappear.For harvesting, the growers use the following equipment: The
traditional “Loan”(special kind of tall ladder, typical in South Tyrol, which consists of a single
wooden pole with horizontal steps) for higher trees (see cover photo), and a harvesting bag made
of heavy cloth. The latter has been substituted largely by the “Tyrolbox”which can be emptied
directly into the bin. The bins are lifted by a tractor-mounted forklift onto the trailer. Larger
operations also use automatically moving harvesting machines. There is a wide range of different
models available at present. Efficient, but rather expensive, is the Dutch Pluk-o-trak machine.
CONCLUSION
South Tyrol offers many advantages for the production of apples, for example, the warm climate,
with its cool nights in autumn before harvest which are typical of mountainous regions. They
improve the color and the sugar level of the fruits. All interesting varieties in the world, from
Gala to Pink Lady, find an ideal habitat. A lot of sunshine as well as sufficient rainfall and water
complete the positive picture. The production structure based on small, family-owned farms is
also advantageous. It permits intensive care, a high degree of mechanization and inexpensive
labor. Research and extension activities are highly specialized and provide information for all the
orchardists.
pack and sell the fruit. The closeness of the most important markets for South Tyrolean apples,
Italy and Germany, is a further advantage.
Apples from all production areas around the world, even from Australia, South America and
South Africa, are coming to Europe. In the last 2 years the prices dropped.
region through know-how, use of new technologies and a constant renewal of our assortment of
varieties and planting systems.
Development of orchard systems in South Tyrol, Italy.
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