Head to the south west area to battle Youngster Calvin.
Youngster Calvin(Prize Money: P64)
Pokémon:
Continue on left then up to fight Bug Catcher Rick or head in to the grass if you want to avoid him. The kid in the grass is not a trainer.
Bug Catcher Rick(Prize Money: P64)
Pokémon:
Continue heading north. The other kid in the grass is also not a trainer. If you stay on the right side while going up, you will be challenged by Youngster . Defeat him and pick up the Pecha Berries(x2) and Oran Berries(x2)berries behind him.
Youngster Allen(Prize Money: P32)
Pokémon:
The path to the right just leads back to a ledge to the previous area. Keep heading left to challenge Lass Tiana. Head south and pick up the Potion there.
Lass Tiana(Prize Money: P80)
Pokémon:
Go back up and then continue left. Your rival will catch up to you and tell you about the DexNav’s Detector Mode.
After the scene, you won't be able to catch the wild Beautifly but it will be added to your Dex. Before heading to the city, go to the south to find a Potion in the dead end corner. Enter the next city afterward.