Pharmacological Characteristics and Control Efficacy of a Novel SDHI Fungicide Pydiflumetofen Against Sclerotinia sclerotiorum

Abstract

Pydiflumetofen is a novel succinate dehydrogenase inhibitor fungicide. In the current research, we determined the sensitivity of 166 Sclerotinia sclerotiorum strains to pydiflumetofen using mycelial growth inhibition method. The results suggest that pydiflumetofen exhibited a strong inhibitory activity against S. sclerotiorum and the EC50 values ranged from 0.0058 to 0.0953 μg ml−1, with a mean EC50 value of 0.0250 μg ml−1. However, the baseline sensitivity was not normally distributed because of a high variation factor. After treatment with pydiflumetofen, cell membrane permeability increases, but exopolysaccharide and oxalic acid production decreases, which contributes to reduced virulence of S. sclerotiorum and leads to failure of disease infection. In addition, protective and curative activity was performed on detached oilseed rape leaves by artificial inoculation. Pydiflumetofen exhibited excellent protective and curative effects against S. sclerotiorum on oilseed rape, and the protective effect was better than the curative effect. Further, field trials were conducted to evaluate the potential of pydiflumetofen in controlling Sclerotinia stem rot (SSR) caused by S. sclerotiorum on oilseed rape. Compared with the currently used fungicides, pydiflumetofen not only exhibited excellent control efficacy against SSR, but also dramatically reduced the dosage of fungicides in the field. Thus, this study provides important references for revealing pharmacological mechanism of pydiflumetofen against S. sclerotiorum and managing SSR on oilseed rape caused by benzimidazole- and dicarboximide-resistant populations.

Impact of Five Succinate Dehydrogenase Inhibitors on DON Biosynthesis of Fusarium asiaticum, Causing Fusarium Head Blight in Wheat

“…Previous studies reported that SDHIs have good effects in the prevention and control of other diseases. For example, pydiflumetofen can effectively inhibit Sclerotinia sclerotiorum , with an average EC 50 value of 0.0250 μg/mL [18]. In addition, boscalid and isopyrazam have a better inhibitory effect on mycelial growth of Aspergillus flavus than Fusarium species.…”

“…Most of the newly developed fungicides are based on the original reactive group as a backbone. At present, SDHIs have been widely applied for controlling many plant diseases [15,16,17,18]. However, SDHIs are rarely used to control FHB, especially in the control of DON production in wheat grains.…”

Resistance risk assessment for a novel succinate dehydrogenase inhibitor pydiflumetofen in Fusarium asiaticum

“…Pydiflumetofen has been registered for use in potatoes, soybean, oilseed rape, grapes and peanuts. 4,23 Owing to its excellent efficacy against FHB, pydiflumetofen has been, since 2019, launched into the market in China to control wheat FHB. To date, however, no data is available regarding the potential pyd-resistance selected in F. asiaticum, or any reports of resistance mechanisms.…”

“…The N‐methoxy group of SDHIs possesses a unique broad spectrum across many crops and diseases. Pydiflumetofen has been registered for use in potatoes, soybean, oilseed rape, grapes and peanuts 4,23 . Owing to its excellent efficacy against FHB, pydiflumetofen has been, since 2019, launched into the market in China to control wheat FHB.…”

Evaluation of exploitive potential for higher bioactivity and lower residue risk enantiomer of chiral fungicide pydiflumetofen

“…S1) is a novel SDHI chiral fungicide that has high efficiency and broad-spectrum bioactivity. For example, a few studies 18,19 have reported that pydiflumetofen exhibited strong inhibitory activity against Sclerotinia sclerotiorum with a mean EC 50 value of 0.0250 μg mL −1 . Neves et al 20 established the baseline sensitivity of Cercospora zeae-maydis with a mean EC 50 value of 0.0040 μg mL −1 , and Hou et al 21 established the baseline sensitivities of Fusarium asiaticum with a mean EC 50 value of 0.0745 μg mL −1 .…”