Wario main here.
It's rare to find a zard main. I've only played 1 in bracket ever, so I'm not the most experienced. None of my training buddies play the character.
But I'd imagine it's similar to Wario's other matchups with heavies, which in my opinion are slightly in Wario's favor. What it comes down to really is what was referenced above. Wario has safer pokes and much better mobility in neutral. He can punish zard's end lag with a variety of safe pokes - fair, bite, bair, chomp, bike whereas most of zard's moveset is quite commital. I'd stay just outside of Zards range and play bait and punish in neutral. Zard has better range and power but mobility and frame data > range and power in this game from my experience. I really don't see Zard winning in neutral or off stage but I'd love to hear the opinion of Zard players.
Off stage, Wario's dash attack out prioritizes Zard's Up B according to this thread:
http://smashboards.com/threads/wario-dash-attack-gimps.417124/
I think Wario's dair may beat zard's up B but I'm not sure.
Zard is one of the easier characters in the game to fart on because of his frame data and huge hurtbox.
But again take this with a grain of salt, as I said before I'm not the most knowledgeable on zard and am very open to the opinions of those more experienced in the matchup.