Hi Calvin, Welcome to GoY. I'm sure there are plenty people on here that can tell you but I bought a vine last summer and have been doing some research. I found this site to be very helpful.
http://apps.rhs.org.uk/advicesearch/Profile.aspx?PID=284#section3
Hope it helps!

Grape vines can live for between 50 and 70 years. If they are being grown to produce wine it is reckoned that they only really come into their own when they are 10 to 15 years old as by then the vine has got its tap root well down into the rock and is drawing up the minerals etc. that give the flavour to the grape and hence the wine. I am trying to remember all my viticulture classes but still feeling a little brain dead from the bug. I do remember that for the first few years they either don't let the grape fruit or if they do don't use for making wine.

I had the pleasure of working with vines 50 years old, cuttings from the Hampton Court vine which is hundreds of years old, (from Henry 8th's time) being the Black Hamburg. I would say that your vine has vine mildew or powdery mildew, Uncinula Necatrix, it appears in June/July can get on the leaves flowers and canes. We used sulphur and sulpher smokes or lime sulphur wash. All unavailable now, but you can use now in the dormant season flowers of sulphur in soft soap painted on the main rods and dust the ground area with sulphur. In June or July spray with Bordeaux mixture

Gosh how did I miss that part of the question Dr B yes indeed powdery mildew. Treat as Dr B has suggested, if the vine is in a greenhouse make sure it is getting plenty of air through and cut away most of the growth each year.

Yes, hard prunung and bring your rods down to a horizontal position, disbud in Feb/March when you put them up again. Don't try to grow too many bunches. I aimed for 66 bunches off 16 main rods in that vinery, with plenty of Hoof & Horn, Dry Blood, Super phosphate and Sulphate of potash.

We certainly visited a vineyard here where they boasted that some of the vines were over a hundred years old, so I'd guess the answers above which suggest that are correct.