An Iowa, USA, seed merchant has legally challenged the US Patent and Trademark Office, saying it erred in granting patents on modifications to plants such as corn, soyabeans and cotton. The federal court has set October 1999 as the date for hearing the petition. The court's action indicates that the patentability of manmade plants remains legally untested, and that places at risk much of the billions of dollars in investments in the biotechnology industries. This has created a panic among big agricultural companies.