|Donwy mildew has 'burnt' off part of this bunch as it has developed.|
In all regions - We can see fresh oilspots from the Secondary Infection on the 13th and 14th of January. These new Downy Oilspots are of a small size and are beginning to turn red. Favourable weather including heavy dews in the Adelaide Hills have cause some advanced Downy Mildew infections to form a mosaic pattern on leaves (below).
|Downy Mildew secondary infection spread. Note the mosaic pattern.|
Secondary infection conditions are quite different to primary infections and can occur outside of a 10:10:24. For a secondary infection to occur there must be existing oilspots in the vineyard or located nearby. Unfortunately this season a high percentage of vineyards have been spreading Downy Mildew into those around them.
2010/2011 Downy Mildew Summary.
1) 10:10:24 Primary Event – 30th October - This was confirmed by the finding of Oilspots from this 10:10:24 Event in mid-November.
2) & 3) Two Downy Mildew Secondary Events (Warm, Wet Nights) 12th and 14th of November.
4) One Downy Mildew Secondary Event (Warm, Wet Night) - 24th of November.
5) One Downy Mildew Secondary Event (Warm, Wet Night)- 7th of December.
6) Two Downy Mildew Secondary Events (Warm, Wet Nights) - 13th and 14th of January.