Relationship of the severity of Septoria tritici blotch of wheat to sowing time, rainfall at heading and average susceptibility of wheat cultivars in the area [Triticum aestivum; Temora, New South Wales]
1990
Murray, G.M. | Cullis, B.R. (New South Wales Agriculture and Fisheries, Wagga Wagga (Australia). Agricultural Research Inst.) | Martin, R.H. (New South Wales Agriculture and Fisheries, Temora (Australia). Agricultural Research and Advisory Station)
The severity of epidemics of Septoria tritici blotch (STB) in wheat, caused by Mycosphaerella graminicola, was recorded for a 38-year period at Temora in southern New South Wales. The disease was rated as severe in 11 years, moderate in 11 and nil to light in 15, while very wet conditions prevented sowing in one year. The correlation of disease severity with environmental and management factors was examined: the correlation was positive with days from sowing to heading and with rainfall and the number of rainy days in the 4-week periods before and after heading; negative with the time of sowing and with mean daily maximum temperature in the 4-week periods before and after heading. Days from sowing to heading were negatively correlated with total rainfall in the same time period. Addition of these terms did not significantly improve the prediction of severity. Modelling showed that the reduction of the average susceptibility of cultivars grown in an area will reduce the severity of STB. It provided justification for minimum disease standards for cultivars to be grown where STB is potentially severe. Further, it explained the distribution of severity of STB in New South Wales.
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