Page 21 - Volume 5, Issue 1, January 2012

© Benaki Phytopathological Institute
Grape downy mildew control in organic farming 19
to the reference product but provided low-
er quantities of elemental copper (the total
copper applied was about 2.2 kg/ha com-
pared with approximately 6.3 kg/ha for the
reference product). The total metallic cop-
per applied with the Labicuper formulation
was extremely low (0.99 kg/ha). Clearly, the
quantities of elemental copper depend on
the formulation used. Copper formulations
used as reference product provided 482 g/
ha of metallic copper per application, Glu-
tex Cu 90 provided 200 g per ha per appli-
cation, and Labicuper provided 99 g per ha
per application. All non-copper based alter-
native products were essentially equally ef-
fective at harvest (Figure 5).
No visual signs of phytotoxicity were ob-
served at any stage during this experiment.
Yield
Figure 6 shows the effect of different
treatments on total yields (t/ha). The high-
est yields were obtained with reference
product followed by the Glutex Cu 90 for-
mulation. These two formulations were sta-
tistically different in comparison with the
untreated control. There were also statisti-
cally different compared with the other test-
ed products. Plants treated with Sporatec
formulation BM-608 did not show signifi-
cantly different results when compared with
yields obtained with untreated control.
Conclusions
Under the experimental conditions of the tri-
al, characterized by moderate disease pres-
sure, all of the products tested gave an effec-
tive control of P. viticola. The best results were
obtained with copper formulations, which
were all very effective. The results showed
that copper formulations (Glutex Cu 90 and
Labicuper) were able to control grape downy
mildew in the field using a third (Glutex Cu
90) or a sixth (Labicuper) of the amount of
copper in comparison with the reference
product (Figure 5). With the results obtained
it was possible to identify alternatives to cop-
per compounds that were less effective than
copper but nevertheless showed an accept-
able level of activity against P. viticola under
medium disease pressure.
The overall conclusion from this study
suggests that in order to minimize copper
accumulation in the soil, flexible control
Figure 6. Effect of tested products on annual production: yields (t/ha). Values with the same letter are not significantly dif-
ferent according to Duncan’s multiple range test (P ≤ 0.05).