Poster Presentation Science Protecting Plant Health 2017

The influence of temperature and incubation time on the incidence of smut disease on sugarcane (#319)

Nurul Hidayah 1 , Shamsul Bhuiyan 1 2 , Karen Aitken 3 , Victor Galea 1
  1. The University of Queensland, Gatton, QLD, Australia
  2. Sugar Research Australia, Woodford, QLD, Australia
  3. Commonwealth Scientific and Industrial Research Organisation , Brisbane, QLD, Australia

Sugarcane smut caused by a basidiomycete fungus, Sporisorium scitamineum, is a serious disease of sugarcane known to cause up to 60% yield losses in susceptible varieties. Temperature is an important factor in plant disease infection and development. This study aimed to determine the influence of temperature and length of exposure to teliospores on the incidence of sugarcane smut in the field. Sugarcane setts were inoculated by dipping them in teliospore suspension (5x106 teliospores /ml water) at various temperatures (15, 25, 30, 35 and 40°C) for 0, 6, 12 and 24 hours respectively. The treatments were performed in controlled environment cabinet with 5 replications consisted of 5 setts per replication. After the allotted incubation period, sugarcane setts were immersed in 2% sodium hypochlorite for 5 minutes then rinsed with tap water to neutralise un-germinated teliospores remaining on the surface. Subsequently the setts were planted in trays of vermiculite and maintained in a growth chamber at 30°C for 15 days.  The germinated setts were transferred to a glasshouse for 15 days and then transplanted in the field according to a randomized block design.  The incidence of smut disease was recorded every week after first detection of smut on week 4 after transplanting. The highest smut incidence (40.39%) was achieved when temperature during inoculation was 30°C. The incidence of smut significantly decreased (5.72%) at 35°C. Sugarcane setts incubated at 40°C failed to germinate. In terms of the influence of length of exposure to smut teliospore, our results showed that sugarcane setts incubated at 0 incubation time (actually 10 minutes) resulted in the lowest smut incidence (3.65%) which is significantly different from those setts incubated at 6, 12 and 24 hours (21.06, 19.63 and 24.68% respectively).