Page 18 - Volume 5, Issue 1, January 2012

© Benaki Phytopathological Institute
La Torre et al. 16
concentrated mainly in May, when there was
99.8 mm of rain. In June and August rainfall
was average for that period, while in July
and September rainfall was low (Figure 1).
Fungicidal effect and amount of copper
provided with the treatments
The spring weather conditions led to
the appearance of symptoms of primary in-
fection of downy mildew in the last week
of May. The first oil-spots appeared on the
24th of May (BBCH 57-Inflorescences ful-
ly developed; flowers separating) due to
the presumed infection by the rain of May
17th , which was the date of the first infec-
tion event. With regard to the fruits, the first
symptoms of grapevine downy mildewwere
observed on June 23 rd (BBCH 75-Berries pea-
sized, bunches hang). The phytosanitary sit-
uation did not show a particularly critical
framework. Continuous monitoring and
prompt applications, as required by the or-
ganic production method, guaranteed that
all of the products tested achieved an effec-
tive anti-downy mildew control.
Figure 2 reports the assessment of dis-
ease incidence on leaves and bunches at the
harvest. The best protection was achieved
with copper formulations used as reference
product and with the Glutex Cu 90 formu-
lation. The Labicuper formulation showed
a lower control of P. viticola than the refer-
ence product and Glutex Cu 90 although
there were no significant differences among
these products. The experimental products
that did not contain copper (Stimulase, My-
co-Sin VIN, Sporatec, Biplantol and BM-608)
provided a control of infection on leaves sig-
nificantly different in comparison with the
untreated control.
Disease severity measured using RAUD-
PC for both leaves and bunches is report-
ed in Figures 3 and 4 respectively. RAUDPC
values in plots treated with copper formu-
lations were lower than the values in plots
treated with alternatives to copper. The
ANOVA showed that there was no signifi-
cant differences between reference prod-
uct, Glutex Cu 90 and Labicuper. Although
protection based on the application of nat-
ural alternatives to copper did not guaran-
tee the same level of control achieved with
formulated copper compounds, it was nev-
ertheless acceptable.
Figure 5 shows the relationship between
the amount of metallic copper applied and
the effectiveness of the treatments. Glutex
Cu 90 formulation guaranteed similar results
Figure 1. Climatic conditions during the experimental field trial .