Black spots

[User196221]

This is a picture from a second year St. Croix vine. I clipped all clusters earlier but left one or two per vine to see how they would do. Hope you can see the black spots on the grapes. At first I thought they might be fly poop but this morning discovered they dont wash off. Any help identifying what this is would be greatly appreciated.

 

[NorCal]

No expert, but looks like early stage black rot.

 

[User196221]

Thanks for your reply...going to spray my vines with Mancozeb tomorrow. Hope this takes care of it.

 

[grapeman]

The picture is not very good for detail but I do not believe it is black rot at all. That affects the foliage first with small yellowish areas on the leaves turning brown and eventually the spores develop on the fruit and they get a generally rotted and dried out appearance. It looks like the spots you have are slightly sunken so it could be anthracnose (or possibly phomopsis). The good news is that the mancozeb should help control it.

 

[user 36973]

Rally is another good choice you should be able to tank mix with your mancozeb. Hits both anthracnose and black rot. I recall reading somewhere that it is supposed to get into the vine's tissue and provide a good resistance for up to 14 days.

 

[grapeman]

Rally (myclobutanil) does work well but you should not use this or any other fungicide in it's class more than two times per year. Alternate it out with another fungicide to help prevent resistance buildup.

 

[kozman]

Hi, first day signup, first day poster.
I thought I had black rot on grapes but now to the help of this thread I have anthracnose. I have it on 5yr old vine Himrod and Reliance seedless. (did not let fruit until the 4th yr.) I have three other vines, concord, meroit I think and the last one don't know but purple.
Hoping to have a great first time table grape harvest. My question. Is there anyway to save this years crop? I did spray them once with Mancozeb in early spring. I also do have Infuse. I live in S.E. Wisconsin.









 

[grapeman]

This also could be phompopsis which can be controlled with mancozeb products also. If anthracnose you will see sunken lesions which generally have a target or eye pattern to them. This looks more like phomopsis. if they all have this then the chances of a good harvest aren't good. You certainly need more than one protective spray in a year.

 

[user 36973]

My Sheridan grapes have this early in the season unless I aggressively manage early spring sprays. This year I applied sulforix to the vines while they were still dormant and before bud swell. I followed that with weekly mancozeb applications to the young growing shoots and clusters. This completely prevented these lesions this year.

 

[kozman]

Great. I think i will cut back vines a little, spray weekly, and go from there. Thanx. Sorry the photo is a little to fluorescent.

 

[kozman]

Thanks to you two people for the replies. I did get a couple bunches from the Vine. I do have a couple of inches of wood chips under my Vines. I am going to rake them out of there as it seems it would be a good place for fungus to breed.