Powdery Mildew

I really have no experience fermenting grapes infected with powdery.

I seem to have very good success by spraying with a product called Champ II I previously used a product called Tenncop which was very similar. I get my products from the Maryland Grape Growers Association Cooperative pesticide purchase program.

It is a copper based fungicide and contrary to Sulphur which is good only for powdery is good for both powdery and downy mildew. It is a protectant and can be used right up to the day of harvest.

This year I have also used Topsin for a pre-bloom spray and again post bloom. It is a systemic and should be limited in use and follow the manufactures suggestions for maximum amounts per acre per year and number of sprays per year. I think that getting good control pre-bloom and immediately post bloom makes a BIG difference for the rest of the year.

I also think it is good practice to put down a post harvest spray or sprays to prevent an innoculum from building up in the vineyard that will become active again next spring. A lot of growers quit spraying after verasion but I think it is best maybe to quit after verasion but begin again for a spray or two post harvest. I know it is hard to do when all you really want to do is cellar chores.

Paul

Thank you for your comment. I have searched the internet, the information on the product package and the MSDS.

The "Ingestion: Slightly toxic if swallowed. This material may produce toxicity if ingested in large quantities."

I have never used any product up to harvest and it is always better to use caution around any pesticide. My last spray of anything so far this year was July 29. I expect to spray again post harvest. The energy transport is in a downward direction this time of year and the roots need all the carbs they can get for next year.

Op Thu, 27 Aug 2009 06:29:00 -0700 (PDT) schreef Strongarm:

I have fermented grapes that were infected by mildew: NO GO!! Like the answers I found on an austrian site, even 5 % infected grapes will influence the taste. Best to do is to sort your grapes before you use them. Only pick the good ones, go for quality instead of quantity.

Nick.