The fall armyworm in Tha Muang, Thailand. Elaine Kurtenbach | AP

A crop-eating pest first detected in China about five months ago is spreading rapidly and could hurt production of key crops critical to the populous nation's food supply, according to the U.S. Department of Agriculture. Damage from the so-called fall armyworm, which gorges on corn, soybeans, cotton, rice, and dozens of other crops, could force China to import more corn, rice or soy to makeup for the shortfall. Before the U.S.-China trade war, China was importing about 60% of all U.S. soybean exports.

The problem comes at a time when Chinese authorities have been trying to boost soybean production to reduce the need for imports. China now ranks as the world's largest importer of soybeans. China produces about 16 million tons of soybeans annually, but it imports more than 80 million tons each year of the commodity used commonly for animal feed and oils. The insect is now found in at least six provinces in China and the risk of it spreading is seen as high. "Private and government-affiliated crop protection experts in China report that FAW has spread much faster than they expected," USDA said in a report posted this week. USDA said most farmers in China lack the training and financial resources to manage against the armyworm effectively. It added "there is a high probability that the pest will spread across all of China's grain production area within the next 12 months." "It's going to be very severe initially until management programs are in place," said Allen Knutson, Texas A&M AgriLife Extension Service entomologist in Dallas. China is already dealing with a livestock crisis involving pork, one of its primary protein sources, putting Beijing is under greater pressure to respond to the armyworm. China has seen at least 129 cases of the African swine fever since August. Rabobank estimates up to 200 million animals could be affected and production could decline by 30%. As a result of the swine fever, China may need to increase the production of other proteins, including chicken. Also, the Asian country may be forced to boost imports of pork, including from the U.S. despite stiff retaliatory tariffs imposed by Beijing.

Similarly, any major crop losses from the armyworm could force China in the coming years to look to imports for more of its corn, soybean, rice and other vital commodities. There are currently tariffs of 25% assessed on some key U.S. crops entering China, including soybeans. Beijing's current retaliatory tariffs on hundreds of U.S.-produced agricultural products already have led the Chinese to seek out other crop suppliers, including South America and European countries. And President Donald Trump's plan to boost tariffs against nearly all of China's imports could lead Beijing to respond with additional duties on U.S. agricultural products. China isn't the only country dealing with the armyworm. Knutsen, the entomologist, noted that voracious insect already is in other parts of the world, including North America and Africa. If Africa is any indication, the armyworm could become costly for China. The USDA said that since 2016 the pest "has caused extensive economic damage across Africa." In the U.S. and Mexico, meantime, the pest has been controlled mainly with chemical pesticides, although the bugs in some regions have developed a resistance to many insecticides. Also, the destructive insect is controlled in corn and cotton in the U.S. to some degree with genetically modified crops. "Officially, Chinese authorities have employed an emergency action plan to monitor and respond to the pest," USDA said in a recent report. It said the armyworm "has no natural predators in China and its presence may result in lower production and crop quality of corn, rice, wheat, sorghum, sugarcane, cotton, soybean, and peanuts among other cash crops." The armyworm was first detected in January in China and confirmed later that month by the ministry of agriculture, which said it was found in Yunnan province. USDA said it believes the armyworm entered China from neighboring Myanmar. The pest was found in India last year and then is believed to have spread to Bangladesh and Myanmar. WATCH: Former agriculture secretary on what farmers want