I've had sluggish growth on quite a few vines this year too. I blame it on the lack of sun and warmth. It's been in the fortys more than it's been in the sixtys, with incessant rain, so the vines are waiting on some heat! We had two days a week ago that it got in the eightys, and I saw an immediate response!
What fungicide did you use? What variety? This has been a bad start for us growers in Ohio. Too cool and too wet. My newer vines have struggled but the older (4+) vines seem to be moving along. It looks as if I will lose a couple of 3 year vines due to the weather. Another thing I suggest is to get a leaf analysis done so that you can tell how your plants are doing. There is a place near Washing CH (Spectrum Analytic) that is cost effective and has an agronomist on staff that is very knowledgeable in viticulture. I do samples every year to guide me on which supplements to add in late winter. For me, if a vine is struggling, I first pinch off all inflorescence I see and fall back on making the vine hardy again (roots and leaves).
That looks like herbicide damage to me. Has anyone sprayed anything near the plants? Any "Weed and feed" added to your lawn? Any neighbors spraying products in their yards? Was your sprayer previously used for herbicides and maybe contaminated?
I'd prune off the low shoots. I would have rubbed them off as soon as the buds opened on the trunk. I like my trunk to be bare. If your vine is going to absorb a weedkiller, the leaves near the ground will be the ones to get it.