Object reference not set to an instance of an object (563477)

Unity Engine
1 
using UnityEngine;
using System.Collections;

public class Sprite_Colection : MonoBehaviour {
   
    public void start(){
        Update ();
    }
    public void Update(){
        Run ();
    }
    public void Run(){
        Collision2D col = new Collision2D();
        OnTriggerEnter (col);
    }
    public void OnTriggerEnter(Collision2D col){
       
        Debug.Log (col.gameObject.name);
        Destroy (col.gameObject);
        if (col.gameObject.name == "item1(clone)") {
            Debug.Log ("detected collision item1");
            Destroy (col.gameObject);
        } else if (col.gameObject.name == "item2") {
            Debug.Log ("detected collision item2");
            Destroy (col.gameObject);
        } else if (col.gameObject.name == "item3") {
            Debug.Log ("detected collision item3");
            Destroy (col.gameObject);
        } else if (col.gameObject.name == "item4") {
            Debug.Log ("detected collision item4");
            Destroy (col.gameObject);
        } else {
            Debug.Log("detected collision but no name match");       
        }
    }
}

this is the code that i am using to detect collisions and when i run the project is is giving me this error:

I need help on whet is causing it please

2

OnTriggerEnter is called by unity when a collision is detected, you are calling it every update with an empty Collision2D Variable that doesn’t have a gameObject associated with it.

3

so how would i call it because what i am trying to do is just have it run in the background and when an object collides it destroys the object

4

OnTriggerEnter will automatically run when something is colliding with it (provided the collider is set as a trigger, of course).

5

yea i fixed it thanks the camera was not lined up properly so it looked like they were colliding but they were not