Bertha, along with Cynthia, the champion of the Elite Four, was mentioned in An Elite Meet and Greet! by Lucian and by Officer Jenny in A Trainer and Child Reunion!.

She made her debut in DP170, where she, along with Ash and his friends, helped Yōshichi get his Magby back from Team Rocket. After chasing them on her jeep, the group battled the trio and got back Magby.

Later, Bertha battled Ash and his Torterra but managed to defeat him relatively easily. She also advised him to be more observant in battles.

[credit to bulbapedia]