Hi Graham,
Did you read the community article I posted about 2 months ago with 6 non chemical ways to control locusts? The herding channels to force large numbers of hopping stage juveniles into pits seems really promising. There are locust swarms now here in Nepal, and my colleagues and contacts in affected village areas said the control methods I outlined are working pretty well. There are pictures too. You have to scroll down in the thread to see the methods as the first entry is only a call for photographs.
I need to edit the article to add a couple more photos of the fried spiced locusts a friend prepared as a snack.