Two naturally occurring orchid phytoalexins, orchinol and loroglossol; a synthetic analog, dehydroorchinol; a possible precursor of orchinol (3,4’-dihydroxy-5-methoxydihydrostilbene); and batatasin III (3,3’-dihydroxy-5-methoxydihydrostilbene) reduced the growth of C. aurantiaca seedlings. These compounds had no effect on the length of the 1st leaves during early stages of development.