Scipio sowing Carthage with salt

[Epictetus]

I was just reading Mary Beard's blog on the Times website and came across this remarkable little statement (emphasis mine):

The other guest of honour was the man who had been Frank's Director of Studies when he was an undergraduate, Betrand Hallward (the first Vice-chancellor of the University of Nottingham, and the man who almost certainly invented the myth that Scipio ploughed salt into the fields when he destroyed Carthage -- see Classical Philology 1986).

I never knew that the source of the sowing-fields-with-salt myth had been identified, much less that the myth was only thirty years old! (This seems strange to me - I could swear I've read about the myth in sources older than this.)

I've been trying to find the article in Classical Philology online, but to no avail.

Does anyone know anything about this?