Tuesday, December 16, 2014

Vintage 2015 / Fighting the Fungus

Following up our discovery of fungus in the vines, we severely thinned out the shoots in all the blocks and got them in a vertical position ready for spraying.
Finally, the weather gods were with us.
Despite a negative medium term weather forecast, this was changed on Saturday to a three day window of opportunity (warm and sunny) to get combination protective and curative spray cover on.

We used  2g/L each of copper and sulphur (protectives for downy and powdery mildews), 4mL/L AgriFos 600[1] and 6mL/100L Bayfidan 250EC[2] ([1]a curative for downy mildew and.[2]a possible curative for powdery mildew).
Normally I don't like adding four components to a spray batch due to possible compatibility problems and phytotoxic reactions but this was an emergency situation and there was really nothing to lose.

The fact that we had rain on the Sunday evening (2mm only) did nothing to renew my confidence in the Bureau of Meteorology's forecasts but, thankfully, it occurred well outside the critical 4 hour rain fastness period.
And another lesson learnt during this exercise?

Don't drop your pruners in the mid row long grass, forget them and then mow over them! 
We now need to wait to see how effective this spraying has been.
Theoretically with both AgriFos and Bayfidan being systemic, they should be quickly absorbed through the leaves and stems into the sap stream and translocated to all parts of the vine. We should start to notice small brown spots on leaves where the downy mildew has been eliminated and hopefully the disappearance of the white 'down' on the bunches.

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