Other generations in ORAS

[Antimorph]

Hello guys. I'm new on this community. I searched for a while on the internet but I couldn't find the answer to my question.
I want to catch a Trubbish so I can participate in the Ditto giveaway. I bought the game 3 days ago and I have played until Mauville city so far.
I am on the Route 110 but I can't find any Trubbish, even with the DexNav.

Do I need to beat the Elite 4 or something so the new generations of pokemon start to appear into the wild?

Thank you for your time!

[Reed]

Best e4. More Pokemon show up

[Antimorph]

Nice! Thank you xD

[Saiman]

Yes, Trubbish isn't released until your battle with Kyogre/Groudon.  But I went ahead and bred you one.  I'll add your friend code and just add mine that is on the left.

[Saiman]

Yeah, E4 is wrong.   It's after your battle with the legendary.   Route 2 gets: lillipup, zorua, zorua.

Rte 110 is: trubbish (common), chatot (average), shellos (rare)