Deleting a programatically added label in c# win app.

Question

hello everyone..
i am trying to make a windows form application in c# using visual studio 2008.
in this i have added 1 button. on form load i am adding one label at run time. 
now i want to delete that label on click of button1. here is my code--->

private void Form1_Load(object sender, EventArgs e)
{
Label lb = new Label();
lb.Text = "hello";
lb.AutoSize = true;
lb.Visible = true;
lb.name = "l1";
lb.Location = new Point(100, 200);
this.Controls.Add(lb);
}

private void button1_Click(object sender, EventArgs e)
{
this.Controls.RemoveByKey(lb);

}
but i am getting a compilation error that " name lb does not exist in the current context"
what is going wrong.. please HELP...!!!