Integrated Management of Septoria Blotches of Wheat: Effect of Sowing Date, Variety and Fungicide

Abstract

The effect of three sowing dates, three bread wheat varieties and two rates o f fungicide on management of Septoria tritici blotch was studied at six environments. Analysis of the data showed that environment significantly affected all the disease and yield parameters taken, indicating that disease development and severity, kernel weight and yield varied with the different seasons and locations. Late sowing significantly reduced septoria development and severity but had no effect on the first disease appearance, kernel weight and yield. Varieties had significant interactions with the environment for all the parameters, except the first septoria evaluation. Septoria development and severity were higher on the susceptible HAR710 than on HAR1685 and HAR604 though they differed with environment.  Kernel weight and yield of the latter two varieties were significantly higher than the other. Variety by sowing date interaction was significant only as far as its influence on kernel weight. HAR604 had a significantly higher seed weight when planted late, while HAR1685 had a higher seed weight when planted at the recommended sowing date. Fungicide application controlled
septoria development well and increased both kernel weight and yield. Fungicide by environment interaction significantly reduced disease development, and increased kernel weight and yield. There was no evidence of interaction between varieties and fungicide applications in reducing the disease or increasing the yield. The study indicated that the use of relatively resistant cultivars or fungicide application has a pronounced positive effect on the management of the disease. The significant effect of environment observed, however, indicates that recommendation on the management of the disease is highly influenced by seasons and/or locations. A significant positive correlation among septoria evaluation methods and their negative correlation with kernel weight and yield, indicate that the use of any one of the methods can effectively measure the disease and its effects on yield.