Armyworms nibble corn leaves in a field in Siping County, northeast China's Jilin Province, Aug. 14, 2012. Armyworm plague broke out in some of China's northern areas in early August and has affected more than 2 million hectares (or 20,000 square kilometers) of corn, millet and paddy crops. Due to prevention and controlling efforts, the plague's impact has been limited so far. (Xinhua