How to make Admob banners not show in every scene

Im trying have admob banner ads in my app and I dont want them to show in every scene but in this case they do and I dont know how to prevent this from happening. Thank you.

using UnityEngine;
using System.Collections;
using admob;

public class Admanager : MonoBehaviour
{

public static Admanager Instance { set; get; }
public string bannerId;
public string videoId;

private void Start()
{

	Instance = this;
	Admob.Instance ().initAdmob (bannerId, videoId);
	DontDestroyOnLoad (gameObject);
	Debug.Log("load?");
}

public void ShowBanner()
{

		Admob.Instance().showBannerRelative(AdSize.Banner, AdPosition.BOTTOM_CENTER, 5);
		Debug.Log("showing?");

	}

}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using admob;

public class DisplayBannerAd : MonoBehaviour
{

	void Start ()
	{

		Admanager.Instance.ShowBanner ();

		Debug.Log("Banner Ad Shown:");

	}

}

Admob.Instance().removeBanner();

when you not want banner to show.