Hello
I’m in Sydney which has a lot of rain lately. I’ve noticed my grape vine which was planted 4 months ago is starting to have some issues. The leaves are turning brown (it starts off like the picture and get worse until the whole leaf is Brown. I also noted the trunk of the vine has had some bark peeling off it.
I’m assuming this is because of the over watering but could it be disease?
Sounds fungal Jaymz - grape vines are prone to fungal attacks - unfortunately the photo did not attach to your query but I'd say excess water (from above) would be a prime cause. There are plenty of fungicides so try that. If not it could be a bacterial disease called Pierce's disease which does the opposite e.g. it blocks the waterflow in the plant and it then just dies off from LACK of water. If this is the problem then you can only remove affected plant parts and dispose of in council green bins.