Number 19 in my countdown of my top 25 favorite "Mystery Science Theater 3000" episodes is perhaps the finest movie ever made on the subject of giant grasshoppers, 517 "The Beginning of the End"!

Synopsis, from the MST3K Amazing Colossal Episode Guide:
"A young couple out for a night of sweet necking is attacked by something off camera. Cops find their destroyed car; then they find the entire city of Ludlow, Illinois demolished, and all the inhabitants gone. The authorities cordon off the area, but they can't stop ace reporter Audrey Ames from discovering that scientist Ed Wainwright (Peter Graves) is growing big honking tomatoes with radiation stored carelessly in a mini-fridge. Turns out some grasshoppers got into his supply and, having drunk lustily, are now growing and reproducing and growing and so look out! Goodbye, Peoria! Adios, Rantoul and Joliet! The hoppers are headed to Chicago, and the military's about to drop the Bomb. But Wainwright, torturing a captive hopper, figures out their mating call. A guy with a bullhorn broadcasts the call from Lake Michigan and every single hopper drowns, unfulfilled."