A worker picks tea at a plantation in Githunguri, 30 km (18 miles) from Kenya's capital Nairobi, January 6, 2012. Kenya, the world's biggest exporter of black tea, has lost a significant part of its tea production for this month due to severe frost in key growing areas, which could cut its foreign exchange earnings, a major industry group said. In this week alone, about 20 million kg of green leaf was damaged by frost, which occurs when temperatures plunge at night after hot days, said Alfred Njagi, general manager of operations at the Kenya Tea Development Agency (KTDA). REUTERS/Thomas Mukoya (KENYA - Tags: AGRICULTURE BUSINESS ENVIRONMENT FOOD)