Baseline sensitivity and control efficacy of pyrisoxazole against Botrytis cinerea

Isopyrazam is a new broad-spectrum, foliar-absorbed and -translocated succinate dehydrogenase inhibitor fungicide. In this study, 159 Botrytis cinerea isolates collected from different geographical regions of Shandong Province of China were characterized for baseline sensitivity to isopyrazam. Furthermore, the protective and curative activity of isopyrazam on strawberry fruit and the control efficacy in the field were also determined. In contrast to its mycelial growth, the spore germination of B. cinerea was inhibited completely by lower concentrations of isopyrazam, about 1 μg ml−1 on yeast-peptone-acetate medium. Frequency distributions of isopyrazam 50% effective concentration (EC50) values were unimodal curves, with mean EC50 values of 0.07 ± 0.04 (standard deviation) and 0.68 ± 0.36 μg ml−1 for the inhibition of spore germination and mycelial growth, respectively. In addition, there was no positive multiple resistance between isopyrazam and other classes of botryticides such as diethofencarb, iprodione, pyrimethanil, or SYP-Z048. In field trials conducted during 2014 and 2015, isopyrazam used at a concentration of active ingredient at 150 and 200 g ha−1 provided a control efficacy ranging from 76.7 to 87.8% on leaves and from 81.5 to 90.7% on fruit. These results suggest that isopyrazam has the potential to play an important role in the management of gray mold.

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Baseline sensitivity and control efficacy of epoxiconazole against Fusarium graminearum in Henan Province, China

European Journal of Plant Pathology ◽

10.1007/s10658-020-02042-5 ◽

2020 ◽

Vol 157 (4) ◽

pp. 825-833

Author(s):

Shengming Liu ◽

Liuyuan Fu ◽

Jinpeng Chen ◽

Shuan Wang ◽

Jinliang Liu ◽

...

Keyword(s):

Fusarium Graminearum ◽

Henan Province ◽

Baseline Sensitivity ◽

Control Efficacy ◽

And Control

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Baseline Sensitivity and Control Efficacy of Pyraclostrobin Against Botryosphaeria dothidea Isolates in China

Plant Disease ◽

10.1094/pdis-07-18-1214-re ◽

2019 ◽

Vol 103 (7) ◽

pp. 1458-1463 ◽

Cited By ~ 4

Author(s):

Kun Fan ◽

Jie Wang ◽

Li Fu ◽

Guo Fu Zhang ◽

Hai Bin Wu ◽

...

Keyword(s):

Control Measure ◽

Mean Value ◽

Cross Resistance ◽

Botryosphaeria Dothidea ◽

Baseline Sensitivity ◽

Control Efficacy ◽

Quinone Outside Inhibitor ◽

Ring Rot ◽

Rot Disease ◽

And Control

Botryosphaeria dothidea is an important fungal pathogen that causes apple ring rot, which can significantly reduce apple yield. Fungicide applications are the main control measure of apple ring rot worldwide. Pyraclostrobin is a quinone outside inhibitor (QoI) fungicide that has yet to be registered for control of B. dothidea in China. Baseline sensitivity of B. dothidea to pyraclostrobin (EC50 of mycelial growth inhibition) was assessed for 97 isolates collected in Shandong Province. The EC50 values ranged from 0.7010 to 7.1378 μg/ml with the mean value of 3.0870 μg/ml and displayed a unimodal frequency distribution. After cultured on fungicide-free PDA medium or on apples for multiple generations, the B. dothidea–resistant isolates (RST) remained resistant to pyraclostrobin, but exhibited similar virulence as the susceptible isolates (ST). Cross-resistance investigation revealed that pyraclostrobin was not cross-resistant to tebuconazole, flusilazole, carbendazim, and iprodione. Field evolution showed that pyraclostrobin at 200 and 250 g a.i./ha provided greater than 80% control efficacy against apple ring rot disease when applied as a therapeutic or preventive fungicide. The efficacy was similar to fungicides that have been registered for apple.

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Baseline sensitivity and control efficacy of fluazinam against Clarireedia homoeocarpa

Crop Protection ◽

10.1016/j.cropro.2020.105290 ◽

2020 ◽

Vol 137 ◽

pp. 105290

Author(s):

Jian Hu ◽

Jiaxuan Wu ◽

Murong Gu ◽

Jiamei Geng ◽

Cheng Guo ◽

...

Keyword(s):

Baseline Sensitivity ◽

Control Efficacy ◽

And Control

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Baseline Sensitivity of Botrytis cinerea to Pyraclostrobin and Boscalid and Control of Anilinopyrimidine- and Benzimidazole-Resistant Strains by These Fungicides

Plant Disease ◽

10.1094/pdis-92-10-1427 ◽

2008 ◽

Vol 92 (10) ◽

pp. 1427-1431 ◽

Cited By ~ 31

Author(s):

C. K. Myresiotis ◽

G. A. Bardas ◽

G. S. Karaoglanidis

Keyword(s):

Electron Transport ◽

Botrytis Cinerea ◽

Spore Germination ◽

Mycelial Growth ◽

Cross Resistance ◽

Vegetable Crops ◽

Baseline Sensitivity ◽

Transport Chain ◽

Resistant Strains ◽

And Control

Fifty-five isolates of Botrytis cinerea collected from vegetable crops were used to determine the pathogen's baseline sensitivity to two new fungicides: boscalid, which inhibits the enzyme succinate dehydrogenase in the electron transport chain, and pyraclostrobin, which blocks electron transport between cytochrome b and cytochrome c1. Measurement of sensitivity to boscalid was based on both inhibition of mycelial growth and spore germination, while measurement of sensitivity to pyraclostrobin was based only on inhibition of spore germination. For both fungicides, the sensitivity distribution was a unimodal curve, with a mean EC50 value (effective concentration that reduces mycelial growth or spore germination by 50%) of 0.033 μg ml-1 for pyraclostrobin and 2.09 and 2.14 μg ml-1 for boscalid based on the inhibition of mycelial growth and spore germination, respectively. No cross-sensitivity relationship was observed between the two fungicides (r = 0.09). In addition, no cross-resistance relationship was observed between these two fungicides with other botryticides: cyprodinil, pyrimethanil, fenhexamid, fludioxonil, and iprodione. Moreover, the control efficacy of the two fungicides was tested against two anilinopyrimidine-resistant and two benzimidazole-resistant isolates, and two of wild-type sensitivity. Both pyraclostrobin and boscalid provided satisfactory control of all six isolates that was independent of the isolate sensitivity to benzimidazoles and anilinopyrimidines. In contrast, carbendazim failed to control sufficiently the benzimidazole-resistant isolates, while cyprodinil failed to provide satisfactory control of the anilinopyrimidine-resistant isolates.

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

Plant Disease ◽

10.1094/pdis-05-18-0763-re ◽

2019 ◽

Vol 103 (1) ◽

pp. 77-82 ◽

Cited By ~ 11

Author(s):

Yabing Duan ◽

Qian Xiu ◽

Haoran Li ◽

Tao Li ◽

Jianxin Wang ◽

...

Keyword(s):

Oilseed Rape ◽

Sclerotinia Sclerotiorum ◽

Field Trials ◽

Cell Membrane Permeability ◽

Sclerotinia Stem Rot ◽

Baseline Sensitivity ◽

Control Efficacy ◽

Pharmacological Mechanism ◽

Excellent Control ◽

And Control

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.

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