SAO PAULO (Dow Jones)--A federal judge banned the use of Bayer CropScience Ltd.'s (506285.BY) transgenic corn just a month after federal biosafety agents approved the product for retail sale, business daily Valor Economico reported Tuesday.

Federal judge Pepita Durski Mazini of the environmental law department in the court's Parana capital city office in Curitiba also blocked the official biosafety agency, CTNBio, from approving transgenic corn in its meeting scheduled for this week. Monsanto Co. (MON) and Syngenta AG (SYT) transgenic corn was up for review for possible commercial approval this week.

Mazini was unavailable for comment.

Parana's governor, Roberto Requiao, who opposes transgenic crops, was also unreachable by phone early Tuesday.

Requiao governs Brazil's No. 1 corn producing state. Corn is Brazil's No. 2 crop behind soybeans, and its popularity with farmers has grown, with corn prices and corn exports on the upswing.

Bayer's LibertyLink corn was approved by CTNBio on May 16, but small-producer lobbies have convinced federal courts that the transgenic corn would be hazardous to native Parana corn.