Whenever the Secretary of Agriculture has reason to believe that any article or articles are being or are practically certain to be imported into the United States under such conditions and in such quantities as to render or tend to render ineffective, or materially interfere with, any program or operation undertaken under this chapter or the Soil Conservation and Domestic Allotment Act, as amended [16 U.S.C. 590a et seq.], or section 612c of this title, or any loan, purchase, or other program or operation undertaken by the Department of Agriculture, or any agency operating under its direction, with respect to any agricultural commodity or product thereof, or to reduce substantially the amount of any product processed in the United States from any agricultural commodity or product thereof with respect to which any such program or operation is being undertaken, he shall so advise the President, and, if the President agrees that there is reason for such belief, the President shall cause an immediate investigation to be made by the United States International Trade Commission, which shall give precedence to investigations under this section to determine such facts. Such investigation shall be made after due notice and opportunity for hearing to interested parties, and shall be conducted subject to such regulations as the President shall specify.