Ten thousand bug-busters gathered early one morning in a poor mountainous area in Shanxi armed with a biological spray containing metarhizium, a parasite that can destroy locusts. The Shanxi provincial Government has mobilised thousands of exterminators, 10 planes and spent 700,000 yuan (HK$651,000) to spread 20 tonnes of pesticide in seriously affected areas. Shanxi farmers had recently watched helplessly as clouds of locusts destroyed at least 400,000 hectares of crops. Elsewhere, locust-extermination teams have been out in force in 11 provinces and regions, including Shandong, Henan, Hebei, Anhui and Shaanxi provinces, Xinjiang Autonomous Region and Tianjin municipality, to wipe out the pests. According to official sources, East Asian locusts have so far destroyed more than one million hectares of crops in these provinces while Italian locusts have hit more than two million hectares of grasslands in Xinjiang province, where the authorities have launched a feathered counter-attack. More than 700,000 specially trained chickens and ducks have been released so they can devour locusts at the foot of Tianshan Mountain. Zhao Xinchun, deputy head of Xinjiang's Pest Extermination Office, said they had helped get rid of nearly 100 million locusts. It was planned to double the number of ducks and chickens next year. The central and local governments have spent more than 35 million yuan on pest-control chemicals and equipment this year as the biggest locust outbreak in 25 years devastated land and crops in the country. Agriculture Ministry officials say hot weather and chronic drought since early spring fuelled the locust outbreak but environmental experts argue China's locust plague is man-made because of malpractices and ignorance rather than merely natural calamities. Locust plagues, which usually occur over a five-year cycle in the Yellow River district and northern China, have been emerging in three-year cycles since the mid-1980s as soil erosion and drought worsened. The infestation has intensified into an annual problem since late 1990s when ecological destruction widened, experts say. Officials claim there are about 1.4 million hectares of locust-friendly 'wasteland' in China which have been 'conquered' by the insect and become their favourite breeding grounds. But environmental experts warn such wastelands are rapidly expanding because of deforestation, soil erosion, soil alkalisation and environmental pollution. 'The frequent drying up of the Yellow River bed and the increasing alkalisation of soil along the Yellow River because of decades of negligence has cultivated a favourable environment for the pest to multiply,' an environmental expert said. 'This is largely a man-made problem. Logging during the Great Leap Forward and the Cultural Revolution destroyed the forests in the upper reaches of most tributaries of the Yellow River, and the adverse soil erosion has led to abnormal sedimentation on lower reaches of the river,' the expert said. Since 1985, the Yellow River has been dry for part of every year, and last year, the worst on record, China's second-longest river flowed for only three months along its lower reaches. Wherever you go in Shanxi province there are no flowing rivers, just sandy riverbeds. And the same is true for Beijing, Hebei and most of the North China Plain. Over-grazing and cultivation of paddy fields has also turned grasslands in northern China into alkaline soil. The desertification problem in northern Jilin province has threatened local animal husbandry. Between 1985 and last year, the grasslands, home to sheep and cattle, had shrunk by 1.8 per cent a year, 16.5 times the degenerating speed for the period from 1955 to 1985. An agriculture expert warned that China had passed a bumper water supply period and it was expected the country would face increasingly serious droughts. 'Whenever there is drought, there are locusts,' he said. 'Locusts threatened one million hectares of land in the 1980s, the threat was extended to 1.6 million hectares in 1999 and has extended to 4.7 million hectares this year.' With lingering drought, it is highly possible that land ruined by sand and salt in Huai River district, Weishan Lake district and northern China will turn into locust-active areas. Dormant locust areas such as the Guangxi Guizhong region, Shandong Jiaodong peninsula and Hebei agricultural region would also probably come under threat again, internal research reports said. They showed that Bohai Sea district and western Hainan Island would join the Yellow River district in becoming regions severely threatened by locusts if the drought worsened. One of the largest locust outbreaks took place in 1944, when 129 counties and four million hectares in Henan, Hebei and Shanxi provinces were overrun. Another outbreak was caused by a misguided mission to kill sparrows accused of eating grain in 1958, at the start of the Great Leap Forward, which eventually led to a plague of insects, especially locusts, followed by a three-year famine in which more than 40 million people starved to death.