The United States should not open its borders to Brazilian soybeans and soyameal until sufficient safeguards are in place to prevent introduction of the devastating soybean rust disease, said Senate Finance Committee chairman Chuck Grassley on Tuesday.
In a letter to Agriculture Secretary Ann Veneman, the Iowa Republican expressed concern that Brazilian shipments may inadvertently spread the fungus to the United States when in transit.
"Contamination through transportation must be addressed in an open and transparent fashion before we import Brazilian soybeans or soybean meal," Grassley said.
US hog and poultry producers have announced plans to import 190,000 tonnes of Brazilian soymeal beginning in April.
Soybean rust has cost farmers in Brazil, the world's No 2 soybean producer, more than $1 billion.
Soy rust is an airborne fungus that causes the leaves of soy plants to fall prematurely and thus reduce yields. If left unchecked, it can cause losses of 80 percent in yields.
The disease has never been found in the continental United States. Hawaii was infected by it in 1994.
The American Soybean Association earlier this month repeated its call for a temporary ban on South American soybean imports due to rust concerns.
Last month, a USDA study concluded that the wind-borne fungus would eventually spread to the United States, but soy imports did not pose a significant threat.
The USDA was expected to issue new soy-import regulations soon to try to slow its spread.