Two diseases in <i>Stylosanthes</i> spp. caused by <i>Colletotrichum gloeosporioides</i> in Australia, and pathogenic specialization within one of the causal organisms

Abstract

Two anthracnose diseases caused by Colletotrichum gloeosporioides have been found in Stylosanthes spp. in northern Australia. The two diseases can be readily distinguished by their symptoms and their pure-culture characteristics. The disease classified as type A was widespread, but the other, type B, was found at only two localities. In spray-inoculation tests under controlled conditions, S. guianensis cv. Endeavour was highly susceptible to type B isolates, and some lines of S. fruticosa, S. humilis, S. scabra and S. viscosa were highly susceptible to the type A isolates. Two pathogenic races of type A were recognized from the reaction of S. viscosa 33941 towards them. The importance of these diseases is discussed, together with aspects of disease dissemination and future control strategies.