Fungicides may have differential efficacies towards the main causal agents of Fusarium head blight of wheat

Abstract

BACKGROUND: Fusarium head blight (FHB) is a complex disease of wheat and barley caused by several Fusarium species. In recent years, a variation in the composition of the FHB community has been observed in several wheat cultivation areas across the world. In detail, F. avenaceum and F. poae increased their frequencies, while, a lower F. graminearum and F. culmorum incidence was simultaneously observed. These shifts within the FHB complex might have been caused by different factors, including the selective pressure caused by fungicides used to control the disease in the field. Therefore, the present study was carried out to evaluate, both in in vitro experiments and in field trials, the activity of commonly used fungicides of wheat (tebuconazole, metconazole, prothioconazole and prochloraz) towards the above mentioned four Fusarium species. RESULTS: A preliminary in vitro assay revealed that low concentrations of all tested fungicides caused the incomplete reduction of fungal development. Furthermore, F. poae and F. avenaceum showed, at the same time, a lower sensitivity to all tested fungicides. In field trials, all fungicides showed an activity against the four Fusarium species. However, F. avenaceum exhibited a reduced sensitivity to metconazole. The lower efficacy of metconazole towards F. avenaceum was also confirmed by an additional in vitro experiment on several F. avenaceum and F. graminearum different strains. CONCLUSION: The selective pressure exerted by the extensive use of certain fungicides may influence population dynamics of Fusarium species due to their different sensitivity.

Antifungal Activity of Chitosan Oligomers–Amino Acid Conjugate Complexes against Fusarium culmorum in Spelt (Triticum spelta L.)

“…However, the extensive use of tebuconazole, metconazole, prothioconazole, prochloraz and other commonly used fungicides of wheat is exerting a selective pressure and is influencing population dynamics of Fusarium species [5]. Moreover, the European legal framework (Article 14 in European Directive 2009/128/EC) enforces their use in a sustainable way, but low concentrations of the aforementioned fungicides may cause an incomplete reduction of fungal development [9]. Hence, alternative control strategies have become the subject of intense research, including biocontrol agents [10], the selection of resistant cultivars [11,12], or agronomic practices (e.g., influence of tillage and cover crop [13]).…”

Naturally Occurring Fusarium Species and Mycotoxins in Oat Grains from Manitoba, Canada

“…The multi-species nature of FHB on oat significantly impacts current management practices for this disease. F. avenaceum , F. langsethiae , and F. poae are more tolerant to ergosterol-biosynthesis-inhibiting azole fungicides than F. graminearum [ 21 ]. Evidence suggests the efficacy of fungicides and biological control treatments against F. graminearum is reduced when other Fusarium pathogens co-occur at infection sites [ 22 ].…”

Perspective: common errors in dose–response analysis and how to avoid them

“…100% at dose = 0), not only will such information be lost, but also the variation between the replicates will be masked. Despite these shortcomings, percentage‐scaling is the most common method used in the pesticide sciences and pharmacology disciplines 22–24 …”

“…Despite these shortcomings, percentage-scaling is the most common method used in the pesticide sciences and pharmacology disciplines. [22][23][24] The zero-one-scaling transformation has also been used and suggested. 3,9 This approach is used when the lower limit l (Fig.…”