Detection of Thiophanate-methyl-resistant Strains in Diplocarpon mail, Causal Fungus of Apple Blotch

2000 ◽  
Vol 66 (1) ◽  
pp. 82-85 ◽  
Author(s):  
Shuhei TANAKA ◽  
Nobue KAMEGAWA ◽  
Shin-ichi ITO ◽  
Mitsuro KAMEYA-IWAKI
Keyword(s):  
Thiophanate Methyl ◽  
Causal Fungus ◽  
Resistant Strains

The genetic profile and molecular diagnosis of thiophanate-methyl resistant strains of Fusarium asiaticum in Japan

2011 ◽  
Vol 115 (12) ◽  
pp. 1244-1250 ◽  
Author(s):  
Haruhisa Suga ◽  
Takashi Nakajima ◽  
Koji Kageyama ◽  
Mitsuro Hyakumachi
Keyword(s):  
Molecular Diagnosis ◽  
Genetic Profile ◽  
Thiophanate Methyl ◽  
Fusarium Asiaticum ◽  
Resistant Strains

scholarly journals Impact of Application Rate and Interval on the Control of Powdery Mildew and Cercospora Leaf Spot on Bigleaf Hydrangea with Azoxystrobin

2004 ◽  
Vol 22 (2) ◽  
pp. 58-62 ◽  
Author(s):  
A. K. Hagan ◽  
J. W. Olive ◽  
J. Stephenson ◽  
M. E. Rivas-Davila
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Application Rate ◽  
Cercospora Leaf Spot ◽  
Thiophanate Methyl ◽  
Hydrangea Macrophylla ◽  
Application Rates ◽  
Erysiphe Polygoni ◽  
Causal Fungus ◽  
Paraffinic Oil

Abstract Efficacy of azoxystrobin (Heritage 50W™) was assessed over a range of application rates and intervals for the control of powdery mildew (Erysiphe polygoni) and Cercospora leaf spot (Cercospora hydrangea) on bigleaf hydrangea (Hydrangea macrophylla) ‘Nikko Blue’. Rooted hydrangea cuttings were transplanted in a pine bark/peat mixture. In 1998 and 1999, azoxystrobin at 0.16 g ai/liter and 0.32 g ai/liter, as well as 0.24 g ai/liter myclobutanil (Eagle 40W™) and 0.84 g ai/liter thiophanate methyl (3336 4.5F™), greatly reduced the incidence of powdery mildew compared with the untreated control where 75% of the leaves of were infected by the causal fungus. When applied at 1-, 2-, and 3-week intervals, both rates of azoxystrobin were equally effective in both years in preventing the development of powdery mildew on bigleaf hydrangea. In 1998, all fungicides except for thiophanate methyl protected bigleaf hydrangea from Cercospora leaf spot. In the last two trials, the incidence of powdery mildew increased significantly as the application rate for azoxystrobin decreased from 0.16 to 0.04 g ai/liter and the application interval was lengthened from 1 to 3 weeks. In general, all rates of azoxystrobin applied on a 3-week schedule failed to provide the level of powdery mildew control needed to produce quality bigleaf hydrangea for the florist and landscape market. When applied at 2-week intervals, myclobutanil was equally or more effective in controlling powdery mildew than any rate of azoxystrobin applied on the same schedule. When compared to the untreated controls, significant reductions in the incidence of powdery mildew on bigleaf hydrangea were obtained with weekly applications of paraffinic oil. No symptoms of phytotoxicity were associated with the use of any of the fungicides screened.

Effects of thiophanate-methyl and azoxystrobin on the composition of Cercospora kikuchii populations with thiophanate-methyl-resistant strains

2006 ◽  
Vol 72 (5) ◽  
pp. 292-300 ◽  
Author(s):  
Iori Imazaki ◽  
Hiromi Iizumi ◽  
Kouji Ishikawa ◽  
Masashi Sasahara ◽  
Nobuko Yasuda ◽  
...  
Keyword(s):  
Cercospora Kikuchii ◽  
Thiophanate Methyl ◽  
Resistant Strains

scholarly journals First Report of Occurrence of Benomyl Resistance in Botrytis cinerea Isolates on Raspberry in Serbia

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 486-486 ◽  
Author(s):  
B. Tanović ◽  
M. Ivanović
Keyword(s):  
Botrytis Cinerea ◽  
Pcr Amplification ◽  
Rubus Idaeus ◽  
Fruit Rot ◽  
Single Spore ◽  
Thiophanate Methyl ◽  
First Report ◽  
Benomyl Resistance ◽  
Development Of Resistance ◽  
Resistant Strains

Botrytis fruit rot, caused by Botrytis cinerea, is one of the major diseases limiting production of raspberries (Rubus idaeus) in Serbia. Yield losses in commercial fields can exceed 50%, especially during periods of rainy, wet weather before harvest. Development of resistance to fungicides with site-specific modes of action is a serious problem in the control of B. cinerea worldwide. To insure the longest possible useful life of a fungicide, an early detection of shifts of sensitivity in pathogen population is crucial (1). The goal of this study was to evaluate sensitivity of B. cinerea isolates from commercial raspberry fields in Serbia to several fungicides that are frequently used: vinclozolin, benomyl, pyrimethanil, and fenhexamid. Initial isolation was done from sporulating berries during harvest. Single-spore isolates were identified based on colony and conidial morphology and by PCR amplification of an expected 0.7-kbp DNA fragment using B. cinerea-specific primer pair C729+/729- (3). Sensitivity of 130 isolates from six localities (20 to 30 isolates per locality) was determined on potato dextrose agar (PDA) amended with fungicides at discriminatory concentrations (1 and 10 mg/liter). Fungicides were suspended in sterile distilled water and added to autoclaved media that had cooled to 50°C. Inverted mycelial plugs (10-mm diameter), which had been cut from the edge of 4-day-old colonies on PDA, were placed on fungicide amended media and incubated for 48 h at 20°C. Treatments were replicated four times and the experiment repeated once. Strain SAS 56, which is sensitive to benzimidazoles and dicarboximides, and strain SAS 405, which is resistant to these fungicide classes, originating from German Collection of Microorganisms and Cell Cultures, were used as standards in the experiment. Isolates that did not grow at 1 mg/liter were designated as sensitive, those that grew at 10 mg/liter were considered highly resistant, and those that grew at 1 mg/liter but not at 10 mg/liter were classified as weakly resistant to all fungicides tested. Values of EC50 for all highly resistant strains were determined in radial growth experiments on PDA supplemented with a range of concentrations (5,000, 2,500, 1,000, and 500 mg/liter) of benomyl or thiophanate-methyl, according to the method described by Leroux and Gredt (2). All tested isolates were sensitive to vinclozolin, pyrimethanil, and fenhexamid. Nine of 130 isolates were highly resistant to benomyl with EC50 values between 1,056 and 1,523 mg/liter. The reference strain SAS 56 had an EC50 value of 0.17 mg/liter, compared to an EC50 value for SAS 405 strain of 1,548 mg/liter. All benomyl resistant isolates were also resistant to thiophanate-methyl and EC50 values ranged from 2,328 to 7,699 mg/liter. To our knowledge, this is the first report of benomyl resistance in isolates of B. cinerea on raspberry in Serbia. References: (1) H. Ishii. Jarq 40:205, 2006. (2) P. Leroux and M. Gredt. Page 1 in: Laboratoire de Phytopharmacie, INRA, Versailles, 1972. (3) S. Rigotti et al. FEMS Microbiol. Lett. 209:169, 2002.

Molecular diagnosis of thiophanate-methyl resistant strains of Fusarium fujikuroi in Japan

Plant Disease ◽  
2021 ◽  
Author(s):  
Fangjing Li ◽  
Ryoji Komura ◽  
Chiharu Nakashima ◽  
Masafumi Shimizu ◽  
Koji Kageyama ◽  
...  
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Molecular Diagnosis ◽  
Previous Investigation ◽  
Inhibitory Concentration ◽  
Isothermal Amplification ◽  
Fusarium Fujikuroi ◽  
Bakanae Disease ◽  
Thiophanate Methyl ◽  
Loop Mediated Isothermal Amplification ◽  
Resistant Strains

Fusarium fujikuroi is the pathogen of rice bakanae disease, and is subclassified into gibberellin and fumonisin groups (G- and F-groups). Thiophanate-methyl, a benzimidazole fungicide, has been used extensively to control F. fujikuroi. Previous investigation showed that F-group strains are thiophanate-methyl sensitive (TMS), while most G-group strains are thiophanate-methyl resistant (TMR) in Japan. The minimum inhibitory concentration (MIC) in TMS strains was 1–10 μg mL-1, while that in TMR strains was higher than 100 μg mL-1. E198K and F200Y mutations in β2-tubulin were detected in TMR strains. A loop-mediated isothermal amplification-fluorescent loop primer (LAMP-FLP) method was developed for diagnosis of these mutations, and was applied to 37 TMR strains and 56 TMS strains. The result indicated that 100% of TMR strains were identified as having either the E198K mutation (41%) or the F200Y mutation (59%), while none of the TMS strains tested showed either mutation. We found one remarkable TMR strain in the F-group which had a F200Y mutation. These results suggest that E198K and F200Y mutations in β2-tubulin contribute to thiophanate-methyl resistance in F. fujikuroi.

scholarly journals Sensitivity of Cercospora beticola to fungicides in Slovakia

2020 ◽  
Vol 23 (3) ◽  
pp. 147-154
Author(s):  
Kamil Hudec ◽  
Milan Mihók ◽  
Tibor Roháčik ◽  
Ľudovít Mišľan
Keyword(s):  
Growth Rate ◽  
Sugar Beet ◽  
Mode Of Action ◽  
Fungicide Resistance ◽  
Cercospora Beticola ◽  
Active Ingredients ◽  
Thiophanate Methyl ◽  
Resistant Strains ◽  
Pathogen Occurrence ◽  
The One

The fungus Cercospora beticola Sacc. is the one of the most important pathogens on the sugar beet. The frequent application of fungicides with the same mode of action increase a risk of development of resistant strains of the pathogen. Occurrence of C. beticola resistant strains has been never researched in Slovakia. In this work, C. beticola isolates were collected from 10 localities of Slovakia and analysed for fungicide resistance in laboratory conditions. Nine fungicides with different mode of action were tested – trifloxystrobin + cyproconazole, kresoxim-methyl + epoxiconazole, azoxystrobin + cyproconazole, thiophanate-methyl + tetraconazole, thiophanate-methyl, prochloraz + propiconazole, picoxystrobin, tetraconazole, and difenoconazole. The results confirmed, that occurrence of fungicide resistance in C. beticola population was established in Slovakia. Different criteria of assessment of fungicide resistance (based on EC50 and on growth rate – inhibition percentage) showed slightly different results, but both criteria confirmed resistant C. beticola strains to thiophanate-methyl, picoxystrobin and difenoconazole. Fields with higher frequency of application of these fungicides significantly supported the development of resistant strains. Assessment of any C. beticola strains have not confirmed reduced sensitivity to active ingredients tetraconazole and prochloraz + propiconazole. The lowest level of risk of fungicide resistance was confirmed in the locality Oslany. It is very important to focus on anti-resistant strategy and reduce of using fungicides on localities, where the occurrence of resistant C. beticola strains was confirmed – Dolné Saliby (thiophanate-methyl and picoxystrobin) and Senec (picoxystrobin and difenoconazole).

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