Fungal diseases of temperate annual pasture legumes in southern Queensland

Abstract

Diseases of temperate annual pasture legumes in subtropical southern Queensland were surveyed during 1992 and 1993. The following pathogenic organisms were recorded: Colletotrichum trifolii, Stemphylium vesicarium, Oidium sp., Uromyces anthyllidis, Uromyces striatus and Pseudopeziza medicaginis from annual Medicago spp.; Rhizoctonia solani and Colletotrichum destructivum from Ornithopus spp.; and Oidium sp. from Trifolium subterraneum. Three of these disease interactions had not been previously recorded in Queensland and 5 were new reports for Australia. Rust was the most frequently observed and widespread disease on annual medics (44% of M. polymorpha samples). All other diseases of annual medics were found infrequently (2–18% of samples). In contrast, both serradella and subterranean clover were relatively free from any diseases.
The years during which the survey was conducted were dry (as low as 31% of mean March–October rainfall) and the expression of disease may have been restricted. Nevertheless, this improved knowledge of diseases of temperate annual legumes in southern Queensland will assist in the future selection and breeding of suitable cultivars for use in the subtropics.