grape vine white powdery stuff affecting fruit

Neuss, Germany

this year, this white stuff on my grape, which never happen before.. what is it ?
sorry for the almost dried leaves and fruit.. took photo a bit too late .. it dried up.

is it powdery mildew ?

Thumbnail by andrew_yek Thumbnail by andrew_yek Thumbnail by andrew_yek Thumbnail by andrew_yek
Contra Costa County, CA(Zone 9b)

Grapes get several diseases, but not all diseases are found all over the world.
They sure do get powdery mildew.

Other ways to find out possible grape diseases is to ask whatever is Germany's equivalent of our Department of Agriculture. Perhaps also there are colleges that specialize in grapes (wine or table use) that would know what diseases are present where you are.

Hummelstown, PA(Zone 6b)

I am almost positive that is powdery mildew.

There are a number of fungicide programs to control powdery mildew but to be most effective they need to be applied at first onset of disease since they are preventive. Copper is one organically approved product.

I would begin a program anyway to protect new growth and reduce powdery mildew innoculum levels for future seasons.

In the US products like Vivando or Pristine or Quintec would be effective. I would consult there to see what products are approved in Germany.

Neuss, Germany

i sprayed copper + lime spray... early spring.. it makes a mess of the whole place.. with blue color..

Hummelstown, PA(Zone 6b)

Copper comes in many formulations...but yes it is blue. There is the traditional bordeaux mixture which is a powder that can go into solution or you can find various liquid formulations. I prefer liquid copper. There are also some biological products like Serenade (Bacillis) which is a bacteria with fungicidal properties that has some activity on powdery mildews.

Did you have a good result?

Contra Costa County, CA(Zone 9b)

Powdery Mildew and other fungi keep on reproducing, keep on trying to invade plant tissues as long as the conditions are right for them.
Spraying only once, at the beginning of the season would protect the leaves that were already growing when it was sprayed. But there is no systemic effect. One spray in the spring will not protect later growth.
You need to keep spraying to protect the new growth (leaf and fruit)as it emerges.

Neuss, Germany

yes , i guess u can say with positiv result. last year i.got.to.enjoy lot of grape and the vine.=itself is healthy.

Contra Costa County, CA(Zone 9b)

Thank you very much for the follow up. Nice to know that a suggestion worked!

Neuss, Germany

u r welcome

Post a Reply to this Thread

Please or sign up to post.
BACK TO TOP