At this time it is H-O-T in North Carolina. We’ve gotten some rain, and I’ve noticed the plants are not nearly so stressed as before. My theory is that when young plants are water stressed they become more susceptible to disease. For several weeks I thought my berries might be shot. I noticed that most berries had some sort of star like scarring on the grapes…after further discussion with the NC State extension office and a chance meeting with Frank Hobson and Sean McRitchie, I came to learn that the berry scarring was caused by a tiny little insect called a “Thrip”. Thrips arrive for a very short period of time during berry development. They were quite common this year and Frank mentioned that he had them as well.
the scarring can cause the berries ot break as they grow and expand. I’ve also noticed this on some of grapes. Sean drove home the point that I am growing wine grapes and not table grapes. As such, berry scarring, smaller berries, etc.. are not necessarily bad things in themselves, wine grapes don’t have to look pretty. That’s important lesson. Sean thought the grapes would grow out of the problems and outside of some of the berry scarring they do seem to be coming along pretty good.
The Easter freeze is still causing some issues in my vineyard. I’ve had to retrain some new cordon and I think in conjunction with the water stress, many of the plants are weakened. For awhile I had it where nearly all varietals were suffering from a puckering of the leaves, which was odd. That might be water stress, remnants of cold injury and possibly a reaction to maybe spraying sulfur when temps got to hot? That’s the most likely culprit.
I ordered and invaluable guide the other day called, “Compendium of Grape Diseases”. That book has some great pictures of foliar and berry damage. In my opinion my sprays “might” be harming some of my berries during the early stages of their development. I have to learn more about this. According to the book,
“Berries sprayed during the early stages of their development are highly sensitive to injury, which may appear as russeting, scarring or even cracking”…I suspect that maybe I am over applying sulfur or need to stop spraying sulfur completely during berry development and rely solely on other fungicides. My suspicions result from observations in the vineyard where clusters deep in the foliage look great, and clusters on sides that didn’t get sprayed look great…in theory it’s supposed to be the opposite. That may be telling me that I need to adjust my sprays. It’s something I need to discuss with a few others.
Early in the year I sprayed mancozeb and sulfur, then I switch to a couple sprays of pristine, now I am spraying 2-3 sprays consisting of maybe a quart of Sevin (beetles are light this year) and mix it with 6 oz (max application rate) of Bayleton which I try and focus on the berry zone just as the berries are closing. DM isn’t a problem right now, but PM could be, and Bayleton is pretty good for PM and Black Rot. Since I don’t foresee harvesting any of my reds in 66 days or less, I think my next spray might be mancozeb (66 day PHI).
I am having to do quite a bit of training of my younger vines which didn’t make it to the wire last year. My deer fence is working great, NO deer damage to speak of this year which has been great.
Overall, as of July 10, I am pretty happy. There is still the possibility that I might take a crop this year…and the grapes overall are holding up ok considering the lack of rain, cold injury, etc..
Here are some pics:
