Pre- and post-penetration behaviour of Colletotrichum gloeosporioides in susceptible and resistnat Hevea clones were studied. Growth of the fungus on the leaf surface of susceptible clones promoted while appressorium formation was promoted on resistant leaves. The movement of nuclei in both epidermal and palisade cells was seen as an early response to infection. After the entry of the pathogen, the host cells first showed a discolouration followed by an extensive disorganisation of epidermal and mesophyll cells resulting in the arrest of fungal development. In tissues of susceptible clones, this reaction was less intense and was restricted to a few cells. Extensive ramification of the pathogen was observed within the leaf tissues and acervuli were formed 72 h after inoculation.