Monitoring of Septoria Blight on Spring Wheat in the Forest-Steppe of Western Siberia
The purpose of this study was to monitor Septoria blight on the leaves and seeds of spring wheat in the forest-steppe zone of Western Siberia and to determine the efficacy of protective measures. The registration of Septoria blight on leaves and seeds was carried out by conventional methods. During the last 10 years Septoria epiphytoty was developed once every three years, every two years from five years local epidemics were observed, mainly in farms with minimal tillage. In comparison with 1978-2001, Septoria epiphytoty occurrence increased 2-2.5 times in the region. Parastagonospora nodorum monitoring on wheat seeds showed that the samples number with an excess of Septoria threshold (5 %) was quite significant and amounted to 40.5 % on spring wheat and 75 % on winter wheat. Epidemic progression occurs when the decade rainfall is 3 times more than average long-term data with the temperature of 14-22 degrees. The disease progresses at the rate of 2-3 % per day, and the threshold decision for fungicides application is achieved in 2-3 days after the Septoria episode onset. Biological efficiency of resistant varieties cultivation in Septoria control was up to 98.5 %, soil tillage - 50 %, forecrops - on the average of 45.9 %. Seed treatment by system preparations restricts Septoria development before earing phase, reducing the multiplicity of fungicides applications, which is economically effective with the epiphytotic (above 40 %) disease forecast.