3. Results
In the two trials, the equipment had a similar performance
as to the total deposit on the foliage, which was
calculated by multiplying the unit deposit on the arti"cial
targets and the LAI (Table 2).
In the "rst trial, the low value of LAI determined in
both systems indicated a high percentage of liquid not
deposited on the vegetation. In the case of the tunnel, this
quantity (62% of the total distributed) was largely recovered
and recycled, thus producing a loss to the soil
which was about half of that of the traditional sprayer.
The e$ciency of the recycling system of the prototype
was also proved in the later trial with higher LAI, where
the deposit on the plant was more consistent. In this case,
both sprayers deposited on the leaves about 70% of the
total spray, but the tunnel sprayer lost to the ground
two-thirds less than the air-blast sprayer.
The amount of recovered and measured tracer is very
similar to the distributed one, with di!erences ranging
between 0 and 14%.
The vertical repartition of the tracer is very good for
both equipment in the earlier trial. The distribution of the
spray by the tunnel sprayer appears particularly uniform
and, unlike the traditional sprayer, shows a good coverage
also at the highest quotes (Fig. 2).
In the second stage, the presence of a higher density of
foliage a!ected the quality of vertical distribution slightly,
for both systems. The poorest depositions were found in
the upper part of the trees for the air-blast sprayer and in
the lower one for the recycling sprayer (Fig. 3).
Penetration in the canopy was measured only in the
second trial and gave poor results for both sprayers. In
the case of the tunnel sprayer, a coverage 38% higher on
the right side of the tree than on the left was found. This is
probably due to the particular position of the shields and
to the type of air circulation which determines the functional
asymmetry of the machine. This asymmetry is also
evident in the greater amount of liquid found in one of
the two collectors, the left one (Fig. 4).
The highest values of losses to the ground were found
with the air-blast sprayer: 57% in the "rst treatment and
31% in the second. The cross distribution pro"le of these
losses is rather uniform in the "rst treatment, while more
concentrated in the second (Fig. 5).
In contrast to the traditional sprayer, the losses to the
ground of the tunnel were 31% with low leaf density and
10% in full vegetation.
In Table 3, the result of the biological controls made
on four major pests present in the Italian peach orchards
is reported. As a general consideration, both sprayers
showed a similar and satisfactory control of the four
pests. Only small di!erences can be observed between the
two systems for S. pennosa and ¹. maior.
Against ¹. maior, the lower infection percentage with
the tunnel sprayer is in accordance with the fact that this
pest a!ects mainly the higher levels of the trees, where the
prototype provides a better coverage. The infection of
S. pennosa (mildew) was very low with both treatments,
but a little higher with the tunnel sprayer, may be due to
the lower volume applied with this equipment.