Disease threshold-based fungicide applications: potential of multi-disease resistance in winter wheat cultivars in Germany

Abstract

The presence of foliar pathogens often leads to yield losses in winter wheat (Triticum aestivum L.), the most important crop in Germany. In this study the efficacy of different host resistance levels of eight wheat cultivars and three fungicide strategies on fungal disease control was studied in terms of yield and net return in field trials at five sites over three crop years. Fungicide treatments included a situation-related strategy in which cultivars were treated individually based on disease control thresholds, a practice-related strategy in which all cultivars were treated after disease thresholds had been exceeded in one cultivar, and an untreated control. Disease severity and incidence differed between cultivars and were reduced by fungicide treatments compared to the untreated control. On average over all locations and years, the Fungicide Treatment Frequency Index (TFI) of all cultivars treated with the situation-related strategy was significantly lower than those treated with the practice-related strategy, except the highly susceptible cultivar JB Asano. A reduction of the TFI by up to 82% was possible in the situation-related strategy. Despite slightly increased yields in the practice-related strategy compared to the situation-related strategy, these could not compensate for the higher fungicide costs in most cases and led to lower net returns. The cultivars with multi-disease resistance showed clear advantages. Their potential benefits are not only demonstrated by the attainment of high yields, but also in fungicide savings without reducing net returns, provided that their disease resistance characteristics are taken into account.

Synergistic Effects of Chemical Fungicides with Crude Extracts from Bacillus amyloliquefaciens to Control Northern Corn Leaf Blight

“…As the identification of highly effective and new chemical inhibitors for NCLB is slow and expensive, traditional fungicides are still used to control NCLB, mainly including triazole fungicides like tebuconazole, flutriafol, and strobilurin fungicides such as pyraclostrobin and azoxystrobin [16,17]. The prolonged application of chemical fungicides has resulted in the development of dominant resistant strains in agricultural fields, leading to a persistent rise in fungicide usage [18,19] and the release of excess chemical agents into the environment, ultimately causing severe ecological damage and agricultural product quality and safety concerns [20,21]. The proportion of mixed fungicide used for chemical disease control has been steadily rising, such as the mixture of tebuconazole and trifloxystrobin, flutriafol and azoxystrobin, among others [22][23][24].…”

Evaluation of Different Triazole Fungicides for the Management of Leaf Rust of Wheat Under Agro-Ecological Zone of District Layyah

“…It is not well understood how resistant cultivars react to fungicides. Some studies reported yield responses under strong disease pressure of rusts; however, did not report the effect of fungicides on their yields (Morgounov et al, 2015;Klocke et al, 2022). The purpose of this research was to evaluate the impact of fungicides on yields for a wheat variety SH-2 with varying degrees of resistance to leaf rust.…”