Effectiveness of isofetamid, a new succinate dehydrogenase inhibitor fungicide, in the control of grapevine gray mold

Abstract

Gray mold is an important disease in grapevines in Chile, and its control depends primarily on the use of fungicides with a single-site mode of action. Botrytis cinerea has a high risk of developing resistance against such fungicides. Therefore, novel chemical options are needed to achieve satisfactory control of gray mold. Isofetamid is a new succinate dehydrogenase inhibitor (SDHI) fungicide with a single-site of action that inhibits cellular respiration and appears to be a new option in the chemical treatment against gray mold. The aim of this study was to determine the effectiveness of isofetamid in controlling grapevine gray mold in Chile. Field trials undertaken in three different commercial vineyards showed that isofetamid controls gray mold to a similar extent as fenhexamid. During 2012 and 2013, 10 B. cinerea isolates were obtained from commercial vineyards in central Chile to determine their sensitivity to isofetamid. The median inhibitory concentration of isofetamid varied between 0.3-10.0 µg mL -1 and 0.6 to >10 µg mL -1 for mycelium and conidia, respectively. The efficacy of isofetamid against B. cinerea in apple bioassays varied between 61-100% and 37.5-100% for mycelium and conidia, respectively. The results of this study demonstrate that isofetamid is a highly effective fungicide against B. cinerea.

Comparative Performance of Reduced-risk Fungicides and Biorational Products in Management of Postharvest Botrytis Blight on Bigleaf Hydrangea Cut Flowers

“…Isofetamid (Astun; OHP, Bluffton, SC) and fluxapyroxad + pyraclostrobin (Orkestra Intrinsic), fungicides that interfere with fungal cellular respiration, effectively reduced the postharvest botrytis blight disease severity and disease progress in all trials (whole-plant spray and dip applications). This finding was like other studies where isofetamid significantly reduced botrytis blight disease severity in bigleaf hydrangea, grape (Vitis vinifera), and strawberry (Fragaria •ananassa) (Baysal-Gurel et al, 2018;Cavotto et al, 2018;Piqueras et al, 2014). Similarly, fluxapyroxad and pyraclostrobin, when applied alone or in combination, effectively managed botrytis blight and other fungal diseases (Chen et al, 2014; Min et al, 2014; Rebollar-Alviter and Fig.…”

“…Recently, SDHI fungicides such as boscalid, isofetamid, and fluxapyroxad have been introduced that effectively manage botrytis blight in various crops, including woody ornamentals Sierotzki and Scalliet, 2013). This fungicide class inhibits B. cinerea growth and development by blocking cellular or mitochondrial respiration (Piqueras et al, 2014). The invention and development of fungicides with new chemical compounds have played crucial roles in maintaining value and stability of production.…”

Design, Synthesis, and Biological Activities of Novel 1,3,5-Trimethylpyrazole-Containing Malonamide Derivatives

“…In most SDHI fungicides, two aromatic moieties are connected directly via a carboxamide. However, isofetamid C (Figure 1) and fluopyram D (Figure 1), in which two aromatic moieties are bridged by an N -ethyl carboxamide or N -oxo-ethyl carboxamide, also exhibit excellent fungicidal activity, demonstrating the possibility of discovering new compounds by modifying the connection between the two aromatic moieties [21,22].…”

Synthesis, Biological Evaluation, and 3D-QSAR Studies of N-(Substituted pyridine-4-yl)-1-(substituted phenyl)-5-trifluoromethyl-1H-pyrazole-4-carboxamide Derivatives as Potential Succinate Dehydrogenase Inhibitors

“…The key synthetic intermediates were characterized by 1 nuclear magnetic resonance (NMR) and ESI-MS, and the title compounds were characterized by 1 H NMR, 13 C NMR, 19 F NMR, and HRMS. X-ray Diffraction.…”

“…Instruments and Chemicals. 1 H NMR, 13 C NMR, and 19 F NMR spectra were taken on a JEOL-500 (JEOL CO., Ltd., Japan) or a Bruker 400 NMR spectrometer (Bruker Corporation, Germany) with tetramethylsilane (TMS) as the internal standard and CDCl 3 or DMSO-d 6 as the solvents. High-resolution mass spectra (HRMS) data were obtained on a Thermo Scientific Q Exactive (Thermo Scientific, USA).…”