Beginning of the End (1957)

Director: Bert I. Gordon
Cast: James Seay, John Close, Morris Ankrum, Peggie Castle, Peter Graves, Richard Benedict, Than Wyenn, Thomas Browne Henry

Synopsis:

An attractive reporter investigating the mysterious destruction of an Illinois town stumbles upon a secret government laboratory conducting radiation experiments on vegetables. The lead scientist is eager to help find out what happened. Together they discover that giant grasshoppers are behind the devastation. Worse yet, thousands of them are headed toward Chicago! Can they be stopped… or is this the BEGINNING OF THE END?