SAN FRANCISCO, March 25 (Xinhua) -- Apple growers in Washington state on the U.S. west Pacific are worried about the possible negative impact of a China-U.S. trade dispute after U.S. President Donald Trump announced high tariffs on Chinese imports worth billions of U.S. dollars, a local radio reported Sunday.

As China threatened to slap retaliatory tariffs on U.S. imports in response to Trump's announcement Thursday, the most worrying group is Washington state's apple farmers, Washington-based KUOW Radio said.

China has been one of Washington's biggest customers among 60 countries around the world that import a third of the crops grown in the state, it said.

According to statistics by the Washington Apple Commission, China was the sixth largest international apple market for the state between 2013-2016.

Todd Fryhover, the commission's president, told the radio that Washington apple growers fret about the prospect of China imposing tariffs in response to U.S. unilateral trade pressure.

"Free trade is something that we all push and look forward to. But we're gonna be cautious and wait ... and see what happens," he said.

According to data released in 2015 by the Economic and Commercial Section of the Chinese Consulate General in San Francisco, Washington is the top state in the United States in terms of the output of apples, cherries, concord grapes and other crops.

China is the largest foreign destination market of Washington state's farm products, the data shows.

Washington, which is among the most trade dependent states in the United States, counts China as its largest trading partner for both imports and exports.

Last year, the state exported more than 18 billion dollars in goods to China, with airplanes and wheat among the top exports, according to U.S. trade data released by the U.S. Census Bureau.