By "whiffy" they mean "having an odor," of which a whiff repels aphids. British wheat has been genetically modified to smell unappetizing:
At least three members of this web site are definitely gluten-intolerant, and can't eat even natural wheat. I'm betting that this British "whiffy wheat" will expand the gluten-intolerant community significantly.
It's not fun--I feel sick enough to want to stay home from work every time I eat a bowl of rice into which a trace of wheat flour blew--but at least, if enough people find themselves unable to eat wheat, it'll be easier for us celiacs to get through the ordeal-of-sharing-the-first-meal-with-a-new-acquaintance. I get so tired of telling people what gluten intolerance is and is not, I don't want to meet anybody who didn't learn all this information along with me in the early 1990s.