OnTriggerEnter problem

Hi guys, my issue is just a simple one, I'm trying to use onTriggerEnter to go to a game over screen should the ball fall from the board in my tilt game, I'm using a large invisible cube underneath the board for this, not sure if that's where I'm going wrong? Here is my current code anyway, any help is appreciated :)

 using UnityEngine;
 using System.Collections;
 
 public class GameOver : MonoBehaviour {
 
     public void onTriggerEnter (Collider collider)
     {
         if (collider.gameObject.tag == "Player") 
         Application.LoadLevel (6);
     }
 }