A comparative study of the chemical composition of essential oils of two very similar species of the Verbenaceae family (Lantana camara and L. radula) revealed that the main components of essential oil of L. camara were germacrene-D (19.8%) and E-caryophyllene (19.7%), while those of L. radula were E-caryophyllene (25.3%), phytol (29.2%) and E-nerolidol (19.0%). We have hypothesized that the observed differences could contribute to the differentiated reaction of the two species of Lantana to the attack of the phytopathogenic fungi Corynespora cassiicola. An experiment, involving C. cassiicola cultivation in culture media containing volatile oils of the two species demonstrated that the oils of L. radula were more fungistatic than the oils of L. camara, in accordance with the in vivo observations. It is likely that E-nerolidol and phytol, only found in the oil of L. radula, play a significant role in the effects of L. radula on C. cassiicola.