Efficacy of the fungicide flutriafol for the control of pineapple sett rot of sugarcane in Australia
Pineapple sett rot of sugarcane is caused by the fungus Ceratocystis paradoxa. It rots the cuttings (setts) after planting and is present in almost all sugarcane growing areas of the world. Recent research has shown the fungicide flutriafol (Sinker®) sprayed on setts at planting can control sugarcane smut infection. Two experiments were established in Bundaberg and one in Woodford, Queensland, to assess the efficacy of flutriafol for the control of pineapple sett rot. Setts of sugarcane were inoculated by spraying a spore suspension (105 spores ml−1 of water) of the fungus onto the cut ends of the setts. Flutriafol was then sprayed on setts at 25 g a.i./ha and 250 g a.i./ha, recommended rates for sugarcane pineapple sett rot and sugarcane smut respectively. Two rates of flutriafol were also mixed with fertiliser (250 and 500 g a.i./ha) and applied beside setts to examine the effect of this treatment on pineapple sett rot control. Two additional fungicides currently registered for pineapple sett rot control, namely propiconazole (Tilt®) and methoxy ethyl mercuric chloride (MEMC) (Shirtan®), were also included in the trials. Results demonstrated that the triazole fungicide flutriafol, sprayed on the setts, significantly controlled pineapple sett rot at both 25 and 250 g a.i./ha., although the low rate was inferior in one of the trials. Flutriafol/fertiliser mix was not effective in controlling the disease. The control achieved with flutriafol was not significantly different to the other registered triazole fungicide propiconazole in two of the three trials. In one trial the registered rate of propiconazole (25 g a.i/ha) was significantly worse than the high rate of flutriafol, while in another trial it was significantly better. Flutriafol was not significantly different to MEMC in two trials but was significantly better in one trial. It was concluded that the flutriafol fungicide can be used to protect sugarcane setts from pineapple sett rot as well as sugarcane smut with a single application.