Potato growers are successfully dealing with the pest that’s been their biggest headche in recent years, an industry group says. The tomato-potato psyllid, discovered in New Zealand in 2006, spreads a bacterium that stunts the growth of potato plants and causes a disease known as zebra chip in the tubers. It also damages tomato and related crops. Potatoes New Zealand chief executive Champak Mehta said the industry had the psyllid well under control thanks to the knowledge gained through research. More