I’ve been a distracted vigneron of late. Lots of things happening at home – some good, some tragic. I’ve managed to get some regular doses of sulfur and kaolin on my vines. I still have to fine tune this as I think I did not start early enough was not regular enough. I am seeing some of those black splotches on green fruit canes. So far, I think I’ve been able to keep the Powdery Mildew off my clusters, but I am seeing weird brown spots on green berries.
Is this Powdery Mildew? Sulfur burn? Pierce’s Disease?
I am not seeing the typical, concentric PD leaf scorch. Berry shrivel has been very minimal and within normal ranges.
Any input would be appreciated.
Spots on unripened berries. The black blotches on canes are Powdery Mildew.
In addition to these brown discolorations, I am seeing some patchy lignification of fruit canes:
Spots on unripened berries. Some patchy lignification of fruiting canes.
Last year, I noted quite a bit of Glassy Winged Sharpshooters in my traps. This year, I am seeing them on canes now and then.
The only preventive measure I have taken was the application of kaolin. I planned to install a Mazzi venturi injector on the irrigation line (for imicloprid administration). But too many things kept me from getting that done.
Now, a few canes have clearly demarcated patchy lignification in a perinodal distribution:
Is this Pierce's Disease?
Close up. One cane on one vine.
Again, there is no significant berry loss or leaf discoloration of scorch and I am not sure whether this pattern of patchy lignification is normal or pathologic.
Has anyone had experience with this?
