Resistance to benzimidazole fungicide in blue mould of citrus in Queensland

1974 ◽  
Vol 14 (70) ◽  
pp. 698 ◽  
Author(s):  
IF Muirhead
Keyword(s):  
Penicillium Italicum ◽  
Thiophanate Methyl ◽  
Blue Mould ◽  
Green Mould

Two of seven isolates of Penicillium italicum Wehmer (blue mould) from different consignments of citrus were resistant in vitro to thiabendazole, benomyl, thiophanate-methyl and carbendazim. The application of thiabendazole and benomyl to Late Valencia oranges inoculated with the resistant isolates failed to prevent the development of blue mould. No resistance was found in seven isolates of P. digitatum Sacc. (green mould).

scholarly journals Salicylic acid and jasmonic acid can suppress green and blue moulds of citrus fruit and induce the activity of polyphenol oxidase and peroxidase

2019 ◽  
Vol 31 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Anam Moosa ◽  
Shahbaz Talib Sahi ◽  
Sajid Aleem Khan ◽  
Aman Ullah Malik
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Disease Severity ◽  
Polyphenol Oxidase ◽  
Disease Incidence ◽  
Citrus Fruit ◽  
Disease Development ◽  
Post Harvest ◽  
Blue Mould ◽  
Green Mould

AbstractThe ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould Penicillium digitatum and blue mould P. italicum on three citrus species Citrus reticulata ‘Kinnow’, C. limon ‘Meyer Lemon’, and C. limetta ‘Mosambi’ was evaluated in a dose-response study. Salicylic acid (SA) and jasmonic acid (JA) were applied to the fruits as a post-harvest dip treatment followed by wound inoculation with the pathogens. Both resistance inducers caused a significantly lower disease severity compared with the infected but non-treated control, whereas disease incidence was not significantly lower than in the control. The efficacy of both SA and JA in reducing disease severity was concentration-dependent; the use of higher concentrations resulted in a greater degree of suppression. All the Citrus species tested in this study showed different responses in terms of disease development. C. limon ‘Meyer Lemon’ showed the highest disease development, and C. limetta ‘Mosambi’ the lowest. To get an insight into the mechanisms underlying the increase in resistance, the activity of defence-related enzymes – peroxidase (POD) and polyphenol oxidase (PPO) – was recorded in SA- and JA-treated fruit peelings. The activity of both enzymes was directly proportional to the concentration of the SA and JA applications. The highest activity of PPO and POD was observed in C. reticulata ‘Kinnow’ and the lowest in C. limon ‘Meyer Lemon’ fruits. This study is the first to document an increase in the activity of PPO and POD in SA- and JA-treated Citrus species in the presence of blue mould and green mould pathogens.

Resistance to azoxystrobin and thiophanate-methyl is widespread in Colletotrichum spp. isolates from the Mid-Atlantic Strawberry Fields

Plant Disease ◽  
2020 ◽  
Author(s):  
Qiuchen Luo ◽  
Anita Schoeneberg ◽  
Mengjun Hu
Keyword(s):  
Cyt B ◽  
Thiophanate Methyl ◽  
Colletotrichum Species ◽  
Predominant Species ◽  
Strawberry Anthracnose ◽  
Colletotrichum Spp ◽  
Moderate Resistance ◽  
High Level ◽  
Host Tissues

Multiple Colletotrichum species have been found to be responsible for strawberry anthracnose, and prevalence of each species seems to vary by regions and/or host tissues. In this study, a total of 200 Colletotrichum isolates were obtained from different strawberry cultivars displaying anthracnose symptoms in the Mid-Atlantic fields. Analysis of g3pdh, tub2, and/or ITS sequences revealed four Colletotrichum species, including C. nymphaeae, C. fioriniae, C. siamense, and C. lineola. C. nymphaeae was the predominant species, representing 90% of all isolates collected. This species was found from all strawberry organs/tissues examined, whereas C. siamense and C. fioriniae were limited to the crown and fruit, respectively. Further, all Colletotrichum isolates were screened for resistance to azoxystrobin in vitro, and all C. siamense isolates were additionally screened for resistance to thiophanate-methyl. The overall frequency of resistance to azoxystrobin and thiophanate-methyl was 48.0 % and 67.0 %, respectively. G143A in the cytochrome b gene (cyt b) was found in all C. nymphaeae and C. siamense isolates with high level of resistance, with EC50 > 100 µg/ml, while F129L was found in two of the five C. nymphaeae isolates with moderate resistance, with EC50 values ranging from 2.6 to 7.8 µg/ml. All C. fioriniae isolates tested were found to be less sensitive to azoxystrobin, with EC50 values ranging from 9.7 to 14.4 µg/ml, despite no mutations detected in cyt b. Moreover, E198A in tub2 was linked with C. siamense isolates resistant to thiophanate-methyl (EC50 > 100 µg/ml). These results revealed that resistance in Colletotrichum spp. to primary fungicides was widespread in the Mid-Atlantic strawberry fields.

scholarly journals Relationship Between Fungicide Sensitivity and Control of Gummy Stem Blight of Watermelon Under Field Conditions

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1780-1784 ◽  
Author(s):  
A. Thomas ◽  
D. B. Langston ◽  
H. F. Sanders ◽  
K. L. Stevenson
Keyword(s):  
Fungicide Resistance ◽  
Field Experiments ◽  
In Vitro Assays ◽  
Didymella Bryoniae ◽  
Fungicide Sensitivity ◽  
Thiophanate Methyl ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
And Control

Gummy stem blight (GSB), caused by the fungus Didymella bryoniae, is the most destructive disease of watermelon and is managed primarily with fungicides. D. bryoniae has developed resistance to many fungicides that were once very effective, including azoxystrobin, boscalid, and thiophanate-methyl. Field experiments were conducted in Tifton (TN) and Reidsville (RV), GA in 2009 and 2010 to establish a relationship between frequency of resistance to a fungicide based on in vitro assays and its efficacy in the management of GSB. Frequency of resistance to boscalid, thiophanate-methyl, and azoxystrobin was >0.80 in isolates collected from nontreated plots in both locations and years. All isolates collected after six applications of boscalid, thiophanate-methyl, or azoxystrobin were resistant to the respective fungicide. All isolates collected from treated and nontreated plots were sensitive to tebuconazole and difenoconazole. GSB severity was assessed on a weekly basis from 63 days after planting. GSB severity in plots treated with boscalid, thiophanate-methyl, or azoxystrobin was not significantly different from that in the nontreated plots (39%, TN-2009; 45%, TN-2010; and 16%, RV-2010). GSB severity in tebuconazole-treated plots (27%, TN-2009; 14%, TN-2010; and 4%, RV-2010) was significantly lower than all other treatments and the nontreated control. There was a consistent negative association between frequency of fungicide resistance and disease control in the field. Thus, knowledge of the frequency of fungicide resistance in the pathogen population will be helpful in selecting the most effective fungicides for the management of GSB in watermelon fields.

scholarly journals Thiophanate-Methyl and Propiconazole Sensitivity in Sclerotinia homoeocarpa Populations from Golf Courses in Wisconsin and Massachusetts

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Paul L. Koch ◽  
Craig R. Grau ◽  
Young-Ki Jo ◽  
Geunhwa Jung
Keyword(s):  
Golf Course ◽  
Golf Courses ◽  
Sclerotinia Homoeocarpa ◽  
Putting Greens ◽  
Thiophanate Methyl ◽  
Development Of Resistance ◽  
History Of ◽  
Intensively Managed ◽  
Pathogen Populations

Management of dollar spot, caused by the fungus Sclerotinia homoeocarpa, is dependent upon repeated fungicide applications in intensively managed turfgrass such as golf course putting greens and fairways. Repeated fungicide applications could potentially select for fungicide-resistant isolates and result in a reduction of disease control. The objectives of this study were to determine the degree of S. homoeocarpa in vitro sensitivity to the fungicides thiophanate-methyl and propiconazole using isolates collected from golf course putting greens, fairways, and roughs; and to determine the relationships of golf course age and fungicide history to the frequency of fungicide-insensitive isolates within the population. More than 1,400 S. homoeocarpa isolates were collected from putting greens, fairways, and roughs at six Wisconsin golf courses and one Massachusetts golf course and subjected to in vitro fungicide sensitivity assays with single discriminatory concentrations of thiophanate-methyl and propiconazole. Five of seven pathogen populations from rough areas were not significantly different from one another in propiconazole sensitivity. These populations were collectively the most sensitive to both fungicides and therefore, served as baseline populations for comparison with fungicide-exposed populations from putting greens and fairways. Greater propiconazole insensitivity was observed in populations collected from fairways and putting greens that received more frequent applications of the fungicide than those isolated from the roughs. In nearly all the golf courses, the frequency of thiophanate-methyl insensitivity was higher among isolates of S. homoeocarpa collected from fairways than from roughs regardless of the age of the golf course or history of benzimidazole use. Thus, while the development of resistance to propiconazole can be predicted in part by the relative frequency of demethylation inhibitor fungicide applications, the occurrence of populations resistant to thiophanate-methyl appears to be unrelated to recent use of the benzimidazole class of fungicides.

Inactivation of Penicillium digitatum and Penicillium italicum under In Vitro and In Vivo Conditions by Using UV-C Light

2013 ◽  
Vol 76 (10) ◽  
pp. 1761-1766 ◽  
Author(s):  
GÜLTEN TİRYAKİ GÜNDÜZ ◽  
FIKRET PAZIR
Keyword(s):  
Potato Dextrose Agar ◽  
Penicillium Digitatum ◽  
Citrus Fruits ◽  
Penicillium Italicum ◽  
Inoculation Methods ◽  
Penetration Ability ◽  
Working Distance ◽  
Uv C

In this study, the effects of UV-C on two of the main wound pathogens of citrus fruits, Penicillium digitatum and Penicillium italicum, were investigated with different inoculation methods in vitro and on oranges. P. digitatum and P. italicum spores were inoculated onto the surface of potato dextrose agar or oranges using spread, spot, wound, and piercing inoculation methods. UV-C treatment for 1 min from a working distance of 8 cm reduced the numbers of P. italicum and P. digitatum by about 3.9 and 5.3 log units, respectively, following spread inoculation under in vitro conditions. Significant reductions were obtained after 1-min UV-C treatments of the tested fungi following inoculation using the spread and spot methods. With inoculation by the wound and piercing methods, the tested spores were not inactivated completely even after 10- and 20-min treatment times, respectively. The application of UV-C (7.92 kJ m−2) on oranges reduced the percentage of oranges infected at least threefold compared with the rate of infection in the untreated control samples. UV-C irradiation could effectively inactivate spores of P. italicum and P. digitatum inoculated by the spread plate and spot inoculation methods under in vitro and in vivo conditions. On the other hand, because of the low penetration ability of UV-C light, the tested fungi were not completely inactivated following inoculation with the wound and piercing methods. UV-C treatment has potential for use in surface decontamination of citrus fruits.

scholarly journals Two Mutations in β-Tubulin 2 Gene Associated with Thiophanate-Methyl Resistance in Colletotrichum cereale Isolates from Creeping Bentgrass in Mississippi and Alabama

Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Joseph R. Young ◽  
Maria Tomaso-Peterson ◽  
Karla de la Cerda ◽  
Francis P. Wong
Keyword(s):  
Amino Acid ◽  
Creeping Bentgrass ◽  
Colony Growth ◽  
Amino Acid Sequences ◽  
Common Disease ◽  
Thiophanate Methyl ◽  
Colletotrichum Cereale ◽  
In Vitro Bioassays ◽  
Β Tubulin

Turfgrass anthracnose, caused by Colletotrichum cereale (≡C. graminicola), has become a common disease of creeping bentgrass putting greens during the summer in Mississippi and Alabama over the last 15 years. Thiophanate-methyl is a single-site mode-of-action fungicide applied to control C. cereale. In vitro bioassays were performed to evaluate the sensitivity of 103 isolates to thiophanate-methyl concentrations ranging from 0.039 to 10 μg/ml. Eighty-three isolates were collected from creeping bentgrass in Mississippi and Alabama that had been exposed to thiophanate-methyl. An additional 20 isolates were included from nonexposed turfgrasses. Radial colony growth in amended media was relative to nonamended media for all in vitro bioassays. With thiophanate-methyl at 10 μg/ml, relative growth of exposed isolates ranged from 77.5 to 130.7% with a mean of 99.3% compared with nonexposed, baseline isolates that ranged from 0.0 to 48.7% with a mean of 20.4%. A representative sample of thiophanate-methyl-exposed and nonexposed isolates was used to determine the mechanism of resistance by comparing amino acid sequences of the β-tubulin 2 protein. All of the thiophanate-methyl-exposed isolates that were sequenced had a point mutation resulting in substitutions from glutamic acid to alanine at position 198 or from phenylalanine to tyrosine at position 200 of the β-tubulin 2 protein. These amino acid substitutions in C. cereale isolates from Mississippi and Alabama appear to confer resistance to thiophanate-methyl and differ from those reported previously for this pathogen.

scholarly journals In vitro and in vivo toxicity of fungicides and biofungicides for the control of verticillium and fusarium wilt of pepper

2021 ◽  
Vol 36 (1) ◽  
pp. 23-34
Author(s):  
Milica Mihajlovic ◽  
Emil Rekanovic ◽  
Jovana Hrustic ◽  
Mila Grahovac ◽  
Brankica Tanovic
Keyword(s):  
Antifungal Activity ◽  
Verticillium Dahliae ◽  
Antagonistic Activity ◽  
In Vitro Assays ◽  
Thiophanate Methyl ◽  
Significant Difference ◽  
By Products ◽  
Pepper Plants

A survey of in vitro and in vivo sensitivity of Verticillium dahliae and Fusarium oxysporum to several commercial fungicides and biofungicides was undertaken. In in vitro assays, the tested isolate of V. dahliae proved to be very sensitive to difenoconazole (EC50 = 0.02 mg/l). However, under greenhouse conditions, the highest efficacy in V. dahliae control on inoculated pepper plants was recorded for a product based on thiophanate-methyl (83.10% compared to control). Among the tested fungicides, the lowest efficacy was recorded for a product based on azoxystrobin (23.10 %) with no significant difference compared to control (p > 0.05). In in vitro assays, the tested F. oxysporum isolate was the most sensitive to prochloraz (EC50 = 0.07 mg/l) and the least sensitive to fluopyram (EC50 = 1075.01 mg/l). In in vivo assay, the highest efficacy was achieved by products based on captan (95.60%), and the lowest by a product based on thiophanate-methyl (54.40%). Antagonistic activity of the bacterium B. subtilis under laboratory conditions was not satisfying. Also, the antifungal activity and spectrum of a tested product based on tee tree oil was not efficient in suppressing pepper wilting caused by V. dahliae and F. oxysporum.

scholarly journals Estimation of the antifungal activity of some preparations against Diaporthe eres under in vitro conditions

2019 ◽  
Vol 72 (4) ◽  
Author(s):  
Ewa Dorota Król ◽  
Barbara Anna Abramczyk ◽  
Beata Zimowska ◽  
Ewa Dorota Zalewska
Keyword(s):  
Natural Products ◽  
Antifungal Activity ◽  
Mycelial Growth ◽  
Fruit Trees ◽  
Thiophanate Methyl ◽  
Natural Origin ◽  
Chemical Groups

Six fungicides from various chemical groups and two natural products, i.e., Biosept Active (grapefruit extract) and Beta-Chikol (chitosan) were tested in vitro against <em>Diaporthe eres</em> isolated from the shoots of fruit trees. The preparations were incorporated in PDA medium to provide final fungicide concentrations of 1, 10, and 100 g cm<sup>−3</sup>. Biosept Active concentrations of 0.05%, 0.075%, and 0.1%, and Beta-Chikol concentrations of 1%, 2%, and 2.5%, respectively. The antifungal activity of the preparations was evaluated based on mycelial growth of <em>D. eres</em> strains after 4 and 8 days of culture and changes in the morphological structures of the fungus. The highest antifungal activity was registered for thiophanate-methyl at all tested concentrations, followed by thiram, which showed the same activity but only at 100 g cm<sup>−3</sup>. Among the preparations of natural origin, Beta-Chikol was more effective against <em>D. eres</em> than Biosept Active. The effects achieved by the former preparation were comparable with those achieved by some of the most effective fungicides tested against <em>D. eres</em>.

scholarly journals ESTUDO DO POTENCIAL DE FUNGOS ENDOFÍTICOS NO CONTROLE DO AGENTE CAUSAL DA FUSARIOSE EM TOMATEIRO

2013 ◽  
Vol 5 (1) ◽  
pp. 50
Author(s):  
Kellem Ângela Oliveira de Sousa ◽  
José Fábio França de Orlanda ◽  
Gustavo De Andrade Bezerra ◽  
Thatyane Pereira De Sousa
Keyword(s):  
Zea Mays ◽  
Aspergillus Niger ◽  
Fusarium Oxysporum ◽  
Manihot Esculenta ◽  
Zea Mays L ◽  
Annona Muricata ◽  
Penicillium Italicum ◽  
Manihot Esculenta Crantz

RESUMO: O presente trabalho objetivou avaliar a capacidade antimicrobiana in vitro, de diferentes extratos de fungos endofíticos, como alternativa no biocontrole de Fusarium oxysporum f.sp. lycopersici. Foram obtidos oito isolados endofíticos de plantas do Cerrado Maranhense e de interesse econômico, a saber: aroeira (Myracrodruon urundeuva Allemão), jenipapo (Genipa americana L.), milho (Zea Mays L.), mandioca (Manihot esculenta Crantz), vinagreira (Hibiscus sabidariffa L.) e graviola (Annona muricata L.). Os isolados endofiticos das espécies foram identificados em Aspergillus niger e Penicillium italicum, com características morfológicas distintas entre as colônias e todos os isolados endofíticos verificou-se crescimento mediano. Para a atividade antimicrobiana, foi realizada a extração dos metabólitos dos isolados endofiticos com os solventes: Acetato de Etila, Clorofórmio e Diclorometano, posteriormente realizado o bioensaio através do confronto direto do antagonista (endófito) sobre o Fusarium Oxysporum f.sp. lycopersici, raça 1, pelo método de difusão em ágar. Os extratos dos isolados endofíticos obtidos do solvente Clorofórmio apresentaram capacidade inibitória, assim interferindo no crescimento do Fusarium oxysporum f. sp. lycopersici raça. Que foram provenientes do caule milho (II) e de jenipapo, com diâmetros de 13mm e 11mm, respectivamente, os outros extratos dos isolados apresentaram halos de inibição inferior. PALAVRAS-CHAVE: antibiose, controle biológico, fitopatógeno.

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