Tuesday, November 4, 2008

Botrytis Risk - Up for Debate?

There is always a decision on whether to spray for Botrytis during flowering. Is it worth it?

For Organic and BioDynamic growers the best from defense is using and open canopy to assist with air flow around the bunches late in the season.

For conventional vineyards consider your Botrytis risk:

Variety


High - Sav. Blanc, Riesling, Grenache, Semillon, Chardonnay, Chenin Blanc, Viognier

Medium - Pinot Gris, Pinot Noir, Chardonnay, big bunched Shiraz, Sangiovese, Mataro/Mouvedre, Petit Verdot, Verdehlo

Low - Small bunched Shiraz, Merlot,

Very Low - Cabernet Sauvignon


The expected rain is likely to be conducive to Bunch Rots and as the young fruit-clusters start flowering (EL 19-20), will need protection. If your vineyard has a history of botrytis spray at full flowering - 80% capfall (EL 25).

If you have been using the same botrytis chemicals for a few seasons in a row consider AVCARE resistance management guidelines.

Click for AWRI Guidelines.There are several different chemical groups recommended for use to control Botrytis bunch rot: Switch (Group I+L), Scala (Group I), Teldor (Group J), carbendazims (Group A), Captan and Chlorothalonil - Bravo & Barrack (all Group Y).

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