China is facing a serious pest infestation in major corn-producing areas, posing a major threat to crops, the Ministry of Agriculture said Tuesday.

As of Tuesday, the armyworm--a caterpillar that can denude crops if its progress is left unchecked--has affected about 3.3 million hectares of farmland, about a tenth of the area under corn in the world's second-largest consumer of the grain, with about 430,000 hectares suffering "serious" infestations, the ministry said in a statement.

China planted about 34.3 million hectares of corn in 2012, according to the state-backed China National Grain & Oils Information Center.

The affected areas include the provinces of Heilongjiang, Jilin, Liaoning and Hebei as well as Inner Mongolia Autonomous Region, the ministry said.

Combined corn output in the five regions accounts for about 45% of China's total corn production.

"The size of the affected areas and the damage are the most serious in a decade," the ministry said.

Write to Zhoudong Shangguan at zhoudong.shangguan@dowjones.com

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(END) Dow Jones Newswires

August 14, 2012 22:24 ET (02:24 GMT)