Anthracnose or phomopsis?

[chrisvt]

I believe we have either anthracnose or phomopsis on a few of our Vanessa and Reliance vines. These plants are in their second year and we did not make a dormant lime sulfur spray this spring.

Is there any organic in-season control for this?

We have anumber of st. croix, marquette and petite pearl vines in this same vineyard which are not showing any signs of this problem - I'm assuming we should remove the infected shoots ASAP so that it doesn't spread?

Apologies for the poor focus on the photo of the shoot.

 

[chrisvt]

I wasn't able to attach more than a single photo to my original post. Here is one of the leaves.

 

[grapeman]

The pictures though blurry suggest anthracnose which is less common than phomopsis. The lesions on the shoot could be either, but anthracnose gives sunken looking lesions whereas the phomopsis looks more like scarring and splitting. On the leaf you have the classic anthracnose look where phomopsis will be more like small yellowish spots.

Best control is an early dormant lime sulfur spray. Not sure what is effective in season organic control.
Check with Terrence Bradshaw from the UVM grape program for his recommendations.

 

[chrisvt]

Thanks, Rich. I'll send Terry a note this morning.

Should I remove the diseased shoots and/or pull up the entire vine, or is it salvageable?

 

[barbiek]

Anthracnose? Just noticed this today on my table grapes been keeping a close watch cuz I had pruned all vines back. Is it to late for lime sulfur spray if so what would you recommend?
Thanks

 

[grapeman]

Use dithane on that. Will type more later.

 

[barbiek]

Thank you grapeman always a pleasure to get your response as I truly respect and admire your expertise looking forward to hearing more

 

[grapeman]

It is hard to tell from that picture but it could be either anthracnose or phomopsis. Generally phomopsis ives more of a split appearance on the shoots and canes wher the anthracnose looks a bit more circular and deeper without a lot of splitting. You need to begin treating with a fungicide for either at about the 1 to 3 inch stage of growth to a maximum of under 10 inches. When you see it, it is too late to prevent it, but you still need to spray tpo prevent it from spreading. Mancozeb products such as dithane or manzate are a very good fungicide for both. Captan has some effect but not as good as the mancozeb products for these. As a bonus they are also effective for black rot and downy mildew.

 

[barbiek]

Thanks a lot rich ordered some dithane