Agemtimz adenophora (Spreng) King & Robinson (Crofton weed) is a significant problem in coastal areas of Queensland and New South Wales, Australia, where it is reduces the carrying capacity of grazing land. Its high reproductive capacity and light windborne fruits are particularly adapted to colonising bare or intermittently bare areas. It is also a problem weed of crops, plantations and pastures in many parts of the world. This weed has an important influence on the development of agriculture, forestry and livestock husbandry. The present study was undertaken to investigate the feasibility of employing the fungus Phaeoramularia sp. as a mycoherbicide to control A. adenophom. The sequence of events leading up to infection of A. adenophora leaves by a conidial suspension of Phaeoramularia sp. was studied using light and electron microscopy. Under optimum conditions, Phaeoramularia sp. could infect A.adenophora 5 days after inoculation via stomata, and incite leaf-spot symptoms and produce conidiophores on the leaf surface within 7 days.