COLONY DESCRIPTIONS, CONIDIUM MORPHOLOGY, AND THE EFFECT OF TEMPERATURE ON COLONY GROWTH OF COLLETOTRICHUM-GLOEOSPORIOIDES ISOLATED FROM STYLOSANTHES SPP GROWING IN SEVERAL COUNTRIES

Colletotrichum gloeosporioides isolates from anthracnose lesions on Stylosanthes spp. growing in Australia, South-east Asia, Africa and Latin America were examined in vitro for colony growth characteristics, conidium morphology, and growth rates at a range of temperatures. Colony growth and conidium morphology varied widely but two distinct groups were separated mainly by conidium uniformity. One group comprised isolates from anthracnose blight lesions on S. guianensis while the other was from more discrete anthracnose symptoms on a range of Stylosanthes spp. Conidia from the former group were more variable in both size and shape than the latter. The described conidium size range of C. gloeosporioides causing Stylosanthes anthracnose should be extended to between 5 and 35-mu-m long x 2.5 and 7.5-mu-m wide. Growth rates also varied between the two groups within global regions supporting the subdivision of this C. gloeosporioides complex. There was some evidence that the Australian and South-east Asian fungi could be grouped separately from the Latin American and African fungi. This reinforces the need for strict quarantine on the movement of Stylosanthes, particularly between these regions.