Therapeutic Effects of Fluorene, Phenanthrene and Xanthene Derivatives on Fungal Diseases of Tomato

DERIVATIVES of 9-hydroxyfluorene-9-carboxylic acid, known as Morphactins, have therapeutic effects on several diseases of tomato1. Apparently, there is no correlation between the morphoregulatory and therapeutic activities of these compounds. Davis et al.2 have shown that unsubstituted fluorene also has a certain effect on Fusarium wilt of tomato. This prompted us to examine several derivatives of fluorene for their therapeutic potencies against two vascular diseases (caused by Fusarium oxysporum f. lycopersici and Verticillium albo-atrum) and one leaf disease (caused by Phytophthora infestans).