BEIJING, May 20 (Reuters) - China's exports to North Korea soared in April from a year earlier, with wigs and fertiliser among major shipments, Chinese customs data showed on Saturday. In January-April, Chinese exports to North Korea leapt to $603 million from $270. North Korea has long suffered from food insecurity and South Korea's DongA Ilbo newspaper reported in mid-February that Pyongyang's food crisis may have deteriorated