Tuesday, February 20th, 2007...2:39 pm

Downy mildew

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I mentioned bad mildew problems in 2004 (see WINE page above) and how we lost the entire crop. Well is really was bad. Look at the state the fruit was in that year.

 

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The fruit was badly affected in 2004. There was no fruit to make any wine with. Lesson learnt. It wont happen again!

We were using all the wrong treatments for it, had terrible canopy mangement so we could not get the sine through the vines and the moisture was sitting around creating humidity in the hot sunshine and the mildew really have a good time of it.

With the downy mildew it comes in after we have rain and/or mist and followed by hot sunshine. The yellow oil mark spotting is the clearest sign that Downy Mildew is there.

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The yellow oilmark spotting on the top side of the leaves- Downy Mildew

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The brown/burnt looking patches on the underside of the same leaf- Downy Mildew

We have had a bit of this appear last week as we had some heavy rain and this seemed to set it off. We were able to control it with a chemical called Coptrace or Liquicop (a soluble copper formulation) which can be used to treat downy mildew later in the season. This is an environmentally friendly product and leaves no harmful residues. In addition we use Sporekill, which is a broad spectrum fungicide and bactericide and seems to work in the control of Downy Mildew.

In 2004 we cut the vines back as much as possible and then burnt as much of the foliage as we could to try to get rid of as many of the fungal spores. We were then able to use a good spray routing to keep it in check and subsequently have made good progress with the crop size and quality in the following years.

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