Dustox

Dustox is attracted to bright lights.  When it flaps its wings, dust is scattered around.  But this is a toxic powder that can be dangerous to other Pokemon.  At night, Dustox is known to strips all the leaves off the trees that are alined amongst a boulevard.
Like Wurmple's other evolved form Beautifly, Dustox suffers from low stats.  Low HP, Attack, Sp. Attack, and Speed.  This makes Dustox very vulnerable to any super-effective moves or moves with a base power of 150 or something like that.  Dustox has a fair Defense stat, but it has a higher Sp. Defense stat.  However, when your highest stat only has a base of 90, you're really not going to see much use with Dustox, I'm afraid.
It has a few decent moves- like Quiver Dance, a move that makes your Sp. Attack, Sp. Defense, and Speed stats go up.  If you get away with using this move 2-3 times in battle, it'll make Dustox fairly stronger.  However, you have low stats as it is, so Dustox can be taken out really easily.  You can teach Dustox Moonlight, a move that restores HP.  If you use Sunny Day to make it sunny in battle, then you'll recover even more HP.  Dustox has a few okay STAB moves, like Silver Wind, Bug Buzz, Sludge Bomb, and U-Turn.  Dustox has a limited amount of options in its movepool, making it a hard Pokemon to work with.
Its ability is the best thing on Dustox you'll get.  It's Shield Dust.  Shield Dust blocks secondary effects from an attack.  For example, Flamethrower is a move that does damage and for its second effect, it might burn its target.  Well, if Flamethrower was to be used on you, then you would only take damage; you would not be burned.  This does not count for moves like Will-o-Wisp or Swagger.  It's a good ability on Dustox, because it needs all the help it can get.
Dustox has low stats, a shallow movepool; everything on it adds up to a Pokemon that isn't exactly the most useful.  If you want to use Dustox, use it for Musicals, Contests, Pokeathlons, anything besides battling!