............provided mineral and biological balance
(good CT) has the potential to eliminate both copper and sulfur applications
in the vineyard. -true?
True . My experience this season (Australia) was CT was able to out
compete Powdery Mildew in Shiraz grape vines, however we were not able to
stop Powdery in cabernet. The grower used sulphur to control the
Powdery in the cabernet and also chose to use it in the Shiraz.
After Veraison CT was again used and no further problems with
Powdery were observed.
The vineyard in question did not have mineral balance in the soil or in
the vines, very few vineyards except the absolute premium vineyards have
mineral balance. This issue is relevant, CT is not a silver bullet
you must address mineralisation as well as biology ie Albrecht, Rheams etc
work.
Unfortunately heavy rain and hail occurred in this vineyard and extensive
splitting of the grapes occurred.
The grower chose to use Ct to reduce the damage from
fruit rotting due to splitting. Warm conditions followed this event and
much of the split gapes dried up. However some grapes did not and near harvest
some of this fruit was decaying on the vines.
The crop was harvested and an independent wine maker assessed the
fruit as being suitable for the reserve label of one of the large wineries in
the area. He gave the fruit a 7 out of 10. This was a great result
considering the grower was concerned that he was going to loose his
entire crop after the splitting event.
We used the CT right up until 2 weeks prior to harvest
However there was a negative in that the Humic acid we used left a
residue that did not look good, next time we will consider using more
fulvic acid and less humics in the CT to reduce the dark coloration
of the CT. I see it as an important advantage in being able to use CT nearer
harvest as this is time when botrytis disease pressure can be
high.
Wine has been made from the grapes with good results so far, no negative
effects from the microorganisms in the CT.
There are some yeast organisms in the CT however the wine makers will be
inoculating with known strains of yeasts to achieve a more predictable
result.
Regards Mike Harvey
New Life Soils
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