Zebra chip

"POTATO crisps—or chips, to those ignorant of the pleasures of a bag of real chips, with lashings of salt and vinegar, after a night in the pub—are the world’s most-nibbled snacks. But that may change if a bizarre, new disease becomes widespread. “Zebra chip”, as this disease is known, causes crisps to develop stripes, and growers and crisp-makers alike are worried. The pattern renders chipping potatoes unsaleable and some farmers have lost much of their crop as a result." (Thanks Rania)