A comparative morphological study of South African avocado and mango isolates ofColletotrichum gloeosporioides

Abstract

South African isolates of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. from avocado and mango are phenotypically as variable as isolates from other countries over the world. Colony colours ranging from pale salmon pink to dark grey green occurred. Isolates from mango were generally less variable than those from avocados. Most isolates produced appressoria terminally on germ tubes and few differences were observed between appressoria of different isolates, their mean length being 14.6 µm. Four different types of conidial shapes were found, and both avocado and mango isolates produced mainly cylindrical conidia with a tapered base and obtuse apex. Conidial length varied considerably, but width remained relatively constant. No correlation was evident between the length/width ratio of conidia and the virulence of isolates when inoculated into avocado and mango.Key words: Colletotrichum gloeosporioides, conidia, morphology, avocado, mango.