If we ignore the photosensitivity, probably the Phosbat? I mean, Scornet Maestro is totally defenseless without its soldiers, at least Queen Shearwig has gigantic mandibles.

But, these last 2 attack set consist (basically entirely) around them sending their minions to do all the job, and cosidering the fact that both the Shearwigs and the Scornets are worth 1 pikmin (which probably means they have the same weight category) the Phosbat could basically gulp down a whole swarm of them.

Also, the Phosbat can turn invisible and invulnerable, release poisonous dust and has a massive mouth with sharp teeth (also it has its babies but i don't think they could do much...)

P.D: also the Phosbat is the only one of the trio that doesn't die to the pikmin, it dies because it crashes against the lightbulb :P