Influence of Nitrogen Supply on the Susceptibility of Wheat to Septoria tritici

Abstract

Nitrogen (N) fertilization is required for achieving high yields in wheat (Triticum aestivum L.) but may enhance the development of Septoria tritici Rob. ex Desm. A study was undertaken to investigate how N supply influences the area under disease progress curve (AUDPC). Two field experiments were carried out in a typical argiudol in 1996 and 1997. Six cultivars were grown at two N treatments (0 and 100–150 kg N/ha) in a split plot design. Percentage of necrosis (severity) of the two upper leaves of each treatment was evaluated three times during the growing season. Height and heading date were also scored and related to the resistance level. In 1996, with weather conditions conducive to the disease, AUDPC values were higher in the fertilized treatment. In 1997, with insufficient rain immediately after inoculation, the disease only progressed faster under N fertilization in the flag leaf, which was exposed to conducive environmental conditions from its appearance. The effect of N fertilization was influenced by the cultivar characteristics, climatic and agronomic conditions. Knowledge that N fertilization promotes the development of S. tritici in conducive conditions will be useful for deciding management strategies of the cultivars and for optimizing conditions for the selection in breeding programmes.

Wheat archive links long-term fungal pathogen population dynamics to air pollution

“…Where samples were available from both plots 8 and 10 (1844, 1862, and 1872), results agreed well. Furthermore, differences in nitrogen fertilization between these two plots were considered too small to influence these two pathogens (29), and reduced phosphate availability may equally decrease abundance of both (30). For the purposes of the long-term pathogen dataset, the data from the two plots were therefore combined into a single series.…”

Estimating grain yield losses caused by septoria leaf blotch on durum wheat in Tunisia

“…Substitution of landraces, which have been identified as resistant to SLB (Sebei and Harrabi, 2008), by high yielding varieties resulted in cropping limited numbers of varieties and hence caused greater incidence of SLB over the last three decades. Continuous wheat cropping, high seeding rates, early planting and excessive use of N fertilizers enhanced SLB proliferation (Fernandez et al, 1998;Simón et al, 2003;Ansar et al, 2010).…”

Recent Advances on Integrated Foliar Disease Management with Special Emphasis in Argentina Wheat Production

“…Management practices such as N fertilization can also affect the expression of wheat foliar diseases [82,84] and the effectiveness of foliar fungicide application [72,82,84,85]. Increasing N rates may cause negative, positive or neutral effect on foliar disease severity, depending on the geographic location [86] and the type of disease.…”

“…The magnitude and direction of the influence of N supply on Septoria leaf blotch severity has been studied with contrasting results [85,87,88,89]. Simón et al [82,84,90] found that in conducive conditions, N fertilization increases the severity of Septoria leaf blotch and discussed the effect of different factors affecting the influence of N supply. Increasing N rates retarded tan spot development [66,69,73,91,92,93,94].…”

“…Increasing N rates retarded tan spot development [66,69,73,91,92,93,94]. However, Bockus and Davis [95] suggested that N applications do not directly affect tan spot severity, but rather appear to reduce disease impact through delayed leaf senescence or that high N rates increase Septoria leaf blotch or tan spot severity due to an increase in crop biomass production, which creates a microenvironment conducive to fungal development in humid regions [82,84,85,96,97]. In addition, experiments carried out in Argentina indicated that yield increase and increase in yield components due to application of tebuconazole was similar in fertilized and non fertilized conditions, despite the increase in the area under disease progress curve under N fertilization [82].…”