American researchers have found that common house flies prefer a deep blue with pinstripes, over the bright yellow traditionally used in fly trap strips.
The findings have led the team at the University of Florida to create the Florida Fly-Baiter.
They say the blue-striped trap killed more than 40,000 flies in a one-month test, with a success rate of 96%.
Urban entomology professor Phil Koehler says it will be available within a year to humanitarian organisations in regions hit by natural disasters and to the general public.
The research was funded by the US Department of Defence, which wants a way to combat flies swarming in the aftermath of a battle.