Leaf -spot diseases on Dichondra spp. (Convolvulaceae).

Dichondra (Dichondra spp.), herbaceous broad-leaved species which are regarded with growing interest as lawn components, are frequently affected by several diseases. Three leaf-spots were studied from lawns in the south of the province of Buenos Aires, Argentina, and their causal agents identified as: Phaeoramularia destruens F. Anderson, Delhey & U. Braun, a new species which is apparently the most destructive of the three, of which only three records, two from the south of Buenos Aires province and the other from the province of Cordoba, are known; Cercospora gossypina Cooke, found in Buenos Aires City as well as in Bahía Blanca and seems to be conspecific with C. ipomoeae G. Winter (previously recorded in Japan and Italy); and finally Alternaria dichondrae Gambogi, Vannacci & Triolo, already known in Argentina as a leaf pathogen of Dichondra in the city of La Plata and its surroundings, so that its known distribution is now extended to the south of the province of Buenos Aires. Since all three fungi produce similar necrotic symptoms, mycological studies are needed to achieve a correct diagnosis.

Key words: Dichondra, leaf spots, Phaeoramularia destruens, Cercospora gossypina, Alternaria dichondrae.