Even with new chemical agents, there appears to be no solution in sight in the short term. “We’ve been experimenting with bait sprayswhere you add chemicals to a substance that the flies like to eat, as a kind of bait.” You then have to spray less, but you still need an effective chemical to put in, he explains. “We have investigated whether you can also add non-chemical substances to the bait to kill the flies, but that is not easy.”