This is a picture of my lovely old vine. It has thrown up seemingly diseased shoots as well as healthy ones. Hope the pictures can be accessed.
http://s1230.photobucket.com/albums/ee485/kasm98/?action=view¤t=DieBack1.jpg
http://s1230.photobucket.com/albums/ee485/kasm98/?action=view¤t=DieBack2.jpg
Its leaves are also showing some kind of discouloration and mottling:
http://s1230.photobucket.com/albums/ee485/kasm98/?action=view¤t=DieBack3.jpg
Have you mulched it with anything?
No, it's in the greenhouse...its roots must go very deep though as it's very old. There was been fabulous grapes on it last year
Hmm..generally it doesn't look bad...just those brown bits...could it be frost?..did you have window open during the cold nights?
Then again..the last leaf looks like something else is wrong... :-\
Have you applied any fertilizer this spring?..if so, did you water it in..? ...I'm thinking of fertilizer scorch.. :-\
nope..no fertislizer...I wondered if it was dieback?..whatever that is??....it is looking worse than the picture depicts
in google images, search for Grapevine diseases - there are some pictures that look a lot like yours, it says Downy Mildew. Perhaps you have a fungal disease there? Do you treat with Bordeaux Mixture?
Could it be red spider mite? look on underside of the leaf with a magnifying glass and look for web and the mites
no..am I supposed to treat with Bordeaux mixture? (am new to vine growing)..Is it too late to do it now? no sign of red spider mite
No, there is no need for spraying unless you know the plant is suffering with fungal problems.
Are those dead brown tops 'crispy' dead? Not 'limp and wet dead' ?
I'm still thinking of scorch..it just looks like it..but there is also high temperature scorch..not just chemical..and looking at your photos all effected parts seem to be the young soft growth that would be more tender and worst effected.
I had look the common problems with grape vine..and scorch is one of those..
"often being seen as dry, papery buff or brown areas. Wilting may occur if the plant is losing more water than it can take up, due either to excessive transpiration or dry soil condititions...excessively high temperatures or the rapid onset of high temperature immediately following cool weather."...sort of what we've experienced recently.
Did you do ample watering and forgot/didn't open door and windows in your GH lately or during last hot spell...?
Fungal problems would show presence of white powdery or furry growth on leaves,,and it is not quite the time of the year for those sort of problems to show up yet.. :-\
yes crispy dead...I will go and look again tomorrow