New Method of Controlling Sugarcane Smut using Flutriafol Fungicide.

Sugarcane smut, caused by Sporisorium scitamineum, is one of the most devastating diseases of sugarcane worldwide. Triazole fungicides such as propiconazole and triadimefon have been routinely used as dip treatments to protect seed-cane (stalk cuttings) from infection by sugarcane smut fungus. However, dip treatments can be applied only to mother stock (nursery) planting materials because of the logistics of dipping large quantities of seed-cane and it is difficult to dispose of the large volumes of waste fungicide solution in an environmentally safe manner. There was a need for a new fungicide that can be applied using more practical methods. The efficacy of flutriafol fungicide to control smut was evaluated in inoculated and infected stalks of a highly susceptible cultivar using various application methods. In a 2007 experiment, flutriafol fungicide was equally effective or better in controlling sugarcane smut as a dip than were two fungicides, propiconazole and triadimefon, registered in Australia. In 2009, two experiments determined the effectiveness of flutriafol when applied by mixing with fertilizer or spraying on the seed-cane at planting. All fungicide treatments significantly suppressed smut in one experiment but, in the second experiment, flutriafol-fertilizer mix treatments were ineffective. In 2010, two experiments verified the efficacy and effective rates of flutriafol against sugarcane smut when applied through existing spray equipment designed to spray fungicide on cuttings as they drop into the planting furrow on a commercial planter. Area under the disease progress curve values of smut incidence were reduced significantly to 47 and 56% with low (125 g a.i. ha^-1) and high (375 g a.i. ha^-1) application rates, respectively, in both experimental sites compared with the inoculated control plots. Sugar yield increased by 46 to 65% in one experiment and 157 to 203% in the second experiment compared with the inoculated control. This research formulated a more practical method of application of flutriafol and suggests greater applications of this fungicide for the management of sugarcane smut.