Yellow canopy syndrome (YCS) of sugarcane, first discovered near Cairns, is characterized by prematurely senescing, bright orange leaves in the lower canopy of the plant. Spread of the disease from northern to southern Queensland and northern New South Wales suggests that the disease is biotic in nature, although symptoms are likely to be modulated by abiotic stresses. Previous research has shown accumulation of starch in early senescing leaves and also disruption of vascular transport, similar to other well-characterized diseases caused by bacteria and viruses. In order to provide clues as to the aetiology of the disease, a range of antimicrobial agents (streptomycin and oxytetracycline (antibiotics), metalaxyl (systemic fungicide) and prochloraz (general fungicide)) were tested on the sugarcane variety Q200 in field trials established in ‘YCS hotspots’ in Ingham and the Burdekin region in the 2016/17 season. Several growth parameters and symptom descriptors were measured during the course of the trials, and results of the analyses will be presented in this paper. Light microscopic examinations of vascular regions of plants in the different antimicrobial treatments were also undertaken, and some fungal and bacterial structures noticed that were abundant in symptomatic leaves. Efforts are being made to identify these microorganisms to provide a catalogue of putative pathogens associated with YCS.