I think the film was made earlier than the 70’s (if it was the one I saw on TV in the early 60’s). It showed locals hopelessly beating at the locusts with branches and the Rapide doing the aerial spraying. What was literally “striking” was the racket of locusts splattering on the windshield as the Rapide ( or possibly the Anson) approached the swarm then, with the wipers going full tilt, the dramatic loss of visibility.
That sounds like the same film, it may well have been made earlier than the 70s but that would be when I saw it.