Looking to upgrade from 2 gal. hand pump sprayer next year. I would love a pull behind ATV with booms (small) just to stay further away from the spray, but they seem larger and more expensive than needed. One of the dolly models instead perhaps with a chargeable battery? Tell me your favorites!
I own four sprayers, two big ones and the ATV mounted ones are Fimco (
FIMCO Sprayers ) , the backpack sprayer came from Home Depot. I don't grow grapes, but use them on a large piece of property that I own.
The biggest is 110 gallon three point hitch for tractor attachment, powered by a PTO driven 6 roller pump, boomless, about $1,700.
I also have a 60 gallon the same as the 110, tractor mounted, PTO / 6 roller pump driven, boomless, about $1,200.
ATV mounted tank sprayers are typically driven by a little electric motor that attaches to your ATV battery and cost $250 - $500, depending upon size, and are a lot more nimble than the ones that you tow behind. It has a boom that's a PIA to deal with when spraying the ground, with both sides folded up vertically, it would be effective driving down the rows and spraying both left and right.
Lastly, a backpack sprayer that holds a few gallons of liquid, you spray with one hand and pump a lever with the other, inexpensive and easy to use / clean, under $100 and probably plenty big enough for 50 vines. There's also an option where you can get a backpack sprayer with a little pump on it powered by rechargeable lithium batteries, they're a little more expensive than the non powered models.
Unless you're planning expansions to your vineyard, the ATV mounted model (look at the boomless options) would be the Cadillac, you could get by with the backpack hand pump model, or splurge a bit for the electric backpack model.
Your thought about keeping the spray behind you is valid, we spray some noxious stuff that you wouldn't want to breathe. When I spray from my tractor, I'm protected inside of an enclosed cab. When using the ATV or backpack sprayer, I always spray while driving upwind.