The fall armyworm can ravage large swathes of crops and has been moving northwards in the world's second-largest corn producer since January. China is set to begin its corn harvest early next month, with the market closely watching output amid tightening stocks.
The pest spread to 25 provinces this year and impacted more than 15 million mu (1 million hectares), officials at China's Ministry of Agriculture and Rural Affairs told reporters.
It did not reach the country's northeast, China's most important corn production region and bread basket for the world's most populous country.
The armyworm has now settled in China, however, and after hibernating in the southwest this winter it will be back to threaten next year's crop, Pan Wenbo, director of the planting administration at the ministry told reporters.
The government is planning early deployment of prevention and control measures next year, Pan said, and will build a long-term strategy for controlling the pest.
This year, most of the damage was done in China's southwest, where some places have seen more than 5% of the corn crop damaged, he said, with the province of Yunnan accounting for 60% of the area where the pest was found.
Sorghum and sugarcane crops have also been impacted, he said, according to a transcript of the briefing.
First found in the Americas, fall armyworm has spread through Africa and Asia since 2016, with the moths capable of flying up to 100 km (60 miles) a night.
The pest cannot be eradicated and its management is both costly and difficult, particularly for China's many small farmers.
(Reporting by Dominique Patton; Editing by Louise Heavens and Tom Hogue)
