What is wrong with my grapes?

[Erikmcclellan]

what's going on here?

This has been happening every year for the last four years. This will affect 80 to 90% of the crop. Can anybody help me? does anybody know what this is? anybody seen this before?

 

[grapeman]

This is classic powdery mildew. You need to prevent it or you will continue getting it. Remove all the infected clusters to help, but you really need some kind of preventative spray program be it organic or regular chemical.

 

[Erikmcclellan]

This is classic powdery mildew. You need to prevent it or you will continue getting it. Remove all the infected clusters to help, but you really need some kind of preventative spray program be it organic or regular chemical.

Thank you very much, we been using sulphur every couple of weeks .... Is there a treatment you recommend?

 

[blumentopferde]

As far as I know sulphur should be fine for powdery mildew. How about spraying it once a week instead of every couple of weeks?

 

[grapeman]

Under high disease pressure it is necessary to reduce the spray interval to every 7 days using sulfur.

 

[Erikmcclellan]

As far as I know sulphur should be fine for powdery mildew. How about spraying it once a week instead of every couple of weeks?

Thanks for the info I will adjust my application schedule.

 

[Erikmcclellan]

Under high disease pressure it is necessary to reduce the spray interval to every 7 days using sulfur.

Thank you for the recommendation. Today I will remove any affected fruit and plant material and start spraying sulphur once a week. I will post a status report to let you all know how it's going

 

[Erikmcclellan]

We'll I started to remove the affected fruit, some rows it's 0% affected and others it's up to 100% affected. We have 11 rows with on average 10 plants per row, I can't believe how much fruit we just threw on the ground it's making me sick.

If there's a silver lining its that not all the fruit is affected, might be able to harvest something this year. Here's some more pics.

 

[Erikmcclellan]

So here is my next question should I remove the branches of the affected fruit?

 

[Bibelljim]

I wouldn't, just the infected fruit.

Unless the leaves show signs of powdery mildew.

 

[Erikmcclellan]

I wouldn't, just the infected fruit.



Unless the leaves show signs of powdery mildew.

Thanks for the reply will do.

 

[cintipam]

I always read that it is important to remove diseased material totally away (actually burn it) because if left nearby the spores will continue to sicken remaining growing vines. Won't that happen here?

Pam in cinti

 

[grapeman]

If the plant material is showing PM, then removal will help control the spread. If not, no need to remove. A more complete spray program will help in the spring next year.

 

[Erikmcclellan]

That's the idea, next year we will start
spraying as soon as the buds appear. And because it seems like were in a high risk area I'll be spraying once a week. Does that sound like a plan that will work?

This year is our fifth year, and with about 125 plants we still haven't had enough grapes to press.

 

[Erikmcclellan]

I noticed while removing infected fruit that some of the fruit have these little drops of juice coming out. Is that a sign of infection also or is that something else?