scholarly journals Resistance to Fluopyram, Fluxapyroxad, and Penthiopyrad in Botrytis cinerea from Strawberry

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Achour Amiri ◽  
Stacy M. Heath ◽  
Natalia A. Peres
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
High Resistance ◽  
Gray Mold ◽  
Cross Resistance ◽  
The Novel ◽  
Resistance Development ◽  
Dehydrogenase Gene ◽  
Resistance Patterns ◽  
Subunit B

Succinate dehydrogenase inhibitors (SDHIs) constitute a mainstay in management of gray mold caused by Botrytis cinerea in strawberry and several other crops. In this study, we investigated the risks of resistance development to three newer SDHIs (i.e., fluopyram, fluxapyroxad, and penthiopyrad) and their cross-resistance with the previously registered boscalid. We investigated the mutations in the SdhB subunit and evaluated their impact on microbial fitness in field populations of B. cinerea. Amino acid substitutions associated with resistance to SDHIs were detected at three codons of the SdhB subunit (BH272R/Y/L, BP225F, and BN230I) in the succinate dehydrogenase gene of field isolates from Florida. The BH272R, BH272Y, BH272L, BP225F, and BN230I mutations were detected at frequencies of 51.5, 28.0, 0.5, 2.5, and 4%, respectively. Strong cross-resistance patterns were evident between boscalid and fluxapyroxad and penthiopyrad but not with fluopyram, except in BH272L, BP225F, and BN230I mutants. All five mutations conferred moderate to very high resistance to boscalid whereas the BH272Y conferred resistance to fluxapyroxad and penthiopyrad. The BH272L, BN230I, and BP225F mutations conferred high resistance to all four SDHIs tested. Resistance monitoring following the first use of penthiopyrad in strawberry fields in Florida in 2013 suggests potential for quick selection for highly resistant populations and warrants careful use of the newer SDHIs. No evidence of major fitness costs due to the mutations in the SdhB subunit was found, which indicates the potential ability of the mutants to survive and compete with wild-type isolates. Our study suggests high risks for rapid widespread occurrence of B. cinerea populations resistant to the novel SDHIs unless appropriate rotation strategies are implemented immediately upon registration.

scholarly journals Differential Effect of SdhB Gene Mutations on the Sensitivity to SDHI Fungicides in Botrytis cinerea

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Thomas Veloukas ◽  
Anastasios N. Markoglou ◽  
George S. Karaoglanidis
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
Gene Mutations ◽  
Gray Mold ◽  
Cross Resistance ◽  
Low Resistance ◽  
Resistance Patterns ◽  
Increased Sensitivity ◽  
High Control

Succinate dehydrogenase inhibiting (SDHI) fungicides constitute a relatively novel fungicide group used for gray mold control caused mainly by Botrytis cinerea. Shortly after registration, resistance was observed in fungal populations that correlated with several mutations in the succinate dehydrogenase complex (complex II). In the current study, 30 B. cinerea isolates possessing five different mutations at three different codons of SdhB (P225F, N230I, and H272L/R/Y) were characterized for their sensitivities to eight SDHI fungicides. The results show different sensitivities and cross-resistance patterns between structurally different SDHIs. P225F mutants were resistant in vitro to all SDHIs tested. Similarly, isolates possessing the H272L mutation were highly resistant to boscalid but showed low to moderate levels of resistance to other SDHIs. The N230I mutants were moderately resistant to boscalid, fluopyram, and fluxapyroxad and showed low resistance levels to isopyrazam, bixafen, fenfuram, benodanil, and carboxin. The H272R mutants showed moderate levels of resistance to boscalid and low resistance levels to isopyrazam, fenfuram, and carboxin but remained sensitive to fluopyram, bixafen, fluxapyroxad, and benodanil. Similarly, the H272Y showed moderate levels of resistance to boscalid and very low resistance levels to isopyrazam, bixafen, fenfuram, and carboxin but showed increased sensitivity to benodanil and fluopyram. Boscalid provided moderate to high control of H272R/Y and N230I mutants in detached fruit assays but provided little control against the H272L and P225F mutants. In contrast, fluopyram controlled H272R/Y mutants and provided moderate levels of control toward H272L, N230I, and P225F mutants. Our findings suggest that sensitivity to SDHIs may vary greatly, dependent on the point mutation in the sdhb subunit.

scholarly journals Activity of the Novel Succinate Dehydrogenase Inhibitor Fungicide Pydiflumetofen Against SDHI-Sensitive and SDHI-Resistant Isolates of Botrytis cinerea and Efficacy Against Gray Mold

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2168-2173 ◽  
Author(s):  
Leiming He ◽  
Kaidi Cui ◽  
Yufei Song ◽  
Tongtong Li ◽  
Ning Liu ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
Gray Mold ◽  
Effective Control ◽  
The Novel ◽  
Baseline Sensitivity ◽  
Single Spore ◽  
Significant Difference ◽  
Low Levels ◽  
Succinate Dehydrogenase Inhibitor

Succinate dehydrogenase inhibitor (SDHI) fungicides are currently the most frequently used fungicides for controlling gray mold. However, isolates of Botrytis cinerea resistant to SDHI fungicides have emerged in the field. Pydiflumetofen is a new SDHI fungicide that can control a variety of fungal diseases, but its efficacy against gray mold and whether the activity of pydiflumetofen is affected by the current SDHI-resistant isolates is currently unknown. The sensitivity of 291 single-spore B. cinerea isolates collected from 2017 to 2019 to pydiflumetofen was determined by spore germination inhibition assays. The mean EC50 value (fungicide concentration resulting in a 50% inhibition compared with that of the control) of pydiflumetofen was 0.06 ± 0.01, 0.07 ± 0.02, and 0.05 ± 0.02 mg/liter in 2017, 2018, and 2019, respectively. There was no significant difference in the sensitivity of B. cinerea to pydiflumetofen among the 3 years. Furthermore, pydiflumetofen at 300 mg/liter effectively controlled gray mold on cucumber leaves (80.9%), and its efficacy was superior to that of boscalid at 400 mg/liter (42.7%). The isolates carrying P225F, N230I, H272Y, and H272R mutations in the SdhB subunit were associated with the less sensitivity of B. cinerea to SDHI fungicides. After establishing the baseline sensitivity of B. cinerea to pydiflumetofen (EC50 of 0.03 ± 0.003 mg/liter), we found that the P225F and H272Y mutant isolates showed low to moderate levels of resistance to pydiflumetofen, and the H272R and N230I mutant isolates showed low levels of resistance. The reduced sensitivity to pydiflumetofen resulted from the positive correlation of pydiflumetofen with the other four SDHI fungicides (i.e., boscalid, fluopyram, isopyrazam, and benzovindiflupyr). These results suggest that pydiflumetofen provides effective control for the management of gray mold but must be used with caution.

Resistance to boscalid in Botrytis cinerea from greenhouse grown tomato

Plant Disease ◽  
2020 ◽  
Author(s):  
Shengming Liu ◽  
Liuyuan Fu ◽  
Huanhuan Tan ◽  
Jia Jiang ◽  
Zhiping Che ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Point Mutations ◽  
Dry Weight ◽  
Henan Province ◽  
Cross Resistance ◽  
Tomato Production ◽  
Grey Mold ◽  
Moderately Resistant

Grey mold, caused by the fungus Botrytis cinerea Pers ex Fr., is one of the most destructive spoilage diseases, severely affecting tomato production in Henan Province, China. Spraying fungicides from the flowering to the harvest stage is a necessary measure to reduce losses associated with B. cinerea infection. However, B. cinerea has developed resistance to fungicides in many countries. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide, and was registered for the control of grey mold. In this study, a total of 269 B. cinerea isolates were collected from tomato in commercial greenhouses in different locations of Henan Province, in 2014 and 2015. The sensitivity and resistance of B. cinerea field isolates were determined based on mycelial growth. The effective concentration 50 (EC50) ranged from 0.11 to 15.92 μg ml−1 and 0.16 to 8.54 μg ml−1, in 2014 and 2015, respectively. The frequency of low resistance to boscalid was 12.6% and 7.6%, and moderate resistance were 2.7% and 1.3%, in 2014 and 2015, respectively. No high-resistant isolates were found in Henan Province, China. Mycelial growth, mycelial dry weight, spore production, and pathogenicity were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. The results of cross-resistance test showed no correlation between boscalid and carbendazim, procymidone, pyrimethanil, fluazinam or fluopyram. In this study, the succinate dehydrogenase gene B (sdhB), C (sdhC), and D (sdhD) were analyzed and compared in sensitive, low and moderately resistant B. cinerea isolates to boscalid. Results showed point mutations occurred simultaneously at sdhC amino acid positions 85 (G85A), 93 (I93V), 158 (M158V), and 168 (V168I) in 4 out of 10 sensitive isolates, 23 out of 26 low and 5 out of 5 moderately resistant B. cinerea isolates to boscalid. No point mutations were found in the sdhB and sdhD genes of all isolates. Furthermore, no point mutations were found in sdhB, sdhC and sdhD genes in 3 out of 26 low resistant B. cinerea isolates to boscalid. Therefore, we speculate the simultaneous point mutations in the sdhC gene may not be related to the resistance of B. cinerea to boscalid. These results suggested that there might be a substitution mechanism for the resistance of B. cinerea to the SDHI fungicide boscalid.

scholarly journals Baseline Sensitivity and Toxic Action of the Sterol Demethylation Inhibitor Flusilazole Against Botrytis cinerea

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2986-2993
Author(s):  
Yong Wang ◽  
Miaomaio Wang ◽  
Letian Xu ◽  
Yang Sun ◽  
Juntao Feng
Keyword(s):  
Botrytis Cinerea ◽  
Plant Pathogens ◽  
Resistance Mechanism ◽  
Point Mutations ◽  
Gray Mold ◽  
Shaanxi Province ◽  
Cross Resistance ◽  
Baseline Sensitivity ◽  
Single Spore ◽  
Demethylation Inhibitor

In the present study, a total of 95 Botrytis cinerea single-spore strains collected from different hosts in Shaanxi Province of China were characterized for their sensitivity to the sterol demethylation inhibitor fungicide flusilazole. The effective concentration for 50% inhibition of mycelial growth (EC50) of flusilazole ranged from 0.021 to 0.372 µg/ml, with an average value of 0.093 µg/ml. Cross-resistance between flusilazole and commonly used fungicides was not detected, and no flusilazole-resistant mutants were induced. Both on detached strawberry leaves and in greenhouse experiments, flusilazole was more effective than the commonly used fungicide carbendazim at reducing gray mold. After culture on PDA plates or detached strawberry leaves, no difference in sclerotia production or pathogenicity was detected between two strains, WG12 (most sensitive to flusilazole) and MX18 (least sensitive to flusilazole). After treatment with flusilazole, however, the two strains lost the ability to produce sclerotia, and oxalic acid and ergosterol contents in mycelium decreased. Interestingly, the inhibition rate of ergosterol content in MX18 was significantly lower than that in WG12. Expression of Cyp51, BcatrD, and Bcmfs1 genes all increased after treatment with flusilazole, especially the Cyp51 and BcatrD genes. However, the expression of Cyp51 gene or BcatrD gene in WG12 and MX18 were significantly different from each other after treatment with flusilazole. In addition, no point mutations in Cyp51 gene were found in MX18. These data suggest flusilazole is a promising fungicide for resistance management of gray mold and also provided novel insights into understanding the resistance mechanism of flusilazole against plant pathogens.

scholarly journals Resistance to the SDHI Fungicides Boscalid, Fluopyram, Fluxapyroxad, and Penthiopyrad in Botrytis cinerea from Commercial Strawberry Fields in Spain

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1306-1313 ◽  
Author(s):  
Dolores Fernández-Ortuño ◽  
Alejandro Pérez-García ◽  
Manuel Chamorro ◽  
Eduardo de la Peña ◽  
Antonio de Vicente ◽  
...  
Keyword(s):  
Amino Acid ◽  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Growing Season ◽  
Gray Mold ◽  
Effective Concentration ◽  
Site Specific ◽  
Resistance Patterns ◽  
Succinate Dehydrogenase Inhibitors

Gray mold, caused by the necrotrophic fungus Botrytis cinerea., is one of the most economically important diseases of strawberry. Gray mold control involves the application of fungicides throughout the strawberry growing season; however, B. cinerea isolates resistant to multiple classes of site-specific fungicides have been recently reported in the Spanish gray mold population. Succinate dehydrogenase inhibitors (SDHI) constitute a relatively novel class of fungicides registered for gray mold control representing new alternatives for strawberry growers. In the present study, 37 B. cinerea isolates previously characterized for their sensitivity to boscalid and amino acid changes in the SdhB protein were used to determine the effective concentration that reduces mycelial growth by 50% (EC50) to fluopyram, fluxapyroxad, and penthiopyrad. The present study was also conducted to obtain discriminatory doses to monitor SDHI fungicide resistance in 580 B. cinerea isolates collected from 27 commercial fields in Spain during 2014, 2015, and 2016. The EC50 values ranged from 0.01 to >100 μg/ml for fluopyram, <0.01 to 4.19 μg/ml for fluxapyroxad, and, finally, <0.01 to 59.65 μg/ml for penthiopyrad. Based on these results, as well as findings from a previous publication, the discriminatory doses chosen to examine sensitivities to boscalid, fluopyram, fluxapyroxad, and penthiopyrad were 100, 15, 1, and 6 μg/ml, respectively. Over the course of the 3-year monitoring period, the overall frequencies of resistance to the four SDHI were 56.9, 6.9, 12.9, and 24.6%, respectively. The frequency of boscalid-resistant isolates decreased from 73 to 41% over the years; however, the fluopyram-resistant isolates increased from 5 to 10% after 1 year of registration. Four SDHI resistance patterns were observed in our population, which included patterns I (30%; resistance to boscalid), II (13.8%; resistance to boscalid and penthiopyrad), III (5.7%; boscalid, fluxapyroxad, and penthiopyrad), and IV (7.9%; resistance to boscalid, fluopyram, fluxapyroxad, and penthiopyrad). Patterns I and II were associated with the amino acid substitutions H272R and H272Y; pattern III was associated only with the H272Y mutation; and, finally, pattern IV was associated with the N230I allele in the SdhB subunit. For gray mold management, it is suggested that the simultaneous use of boscalid and penthiopyrad should be limited to one application per season; however, fluxapyroxad and, especially, fluopyram could be used as valid SDHI alternatives for gray mold control, although they should be applied with caution.

scholarly journals Sources of Primary Inoculum of Botrytis cinerea and Their Impact on Fungicide Resistance Development in Commercial Strawberry Fields

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1761-1768 ◽  
Author(s):  
Michelle Souza Oliveira ◽  
Achour Amiri ◽  
Adrian I. Zuniga ◽  
Natalia A. Peres
Keyword(s):  
United States ◽  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Integrated Approach ◽  
The United States ◽  
Gray Mold ◽  
Resistance Development ◽  
Primary Inoculum ◽  
Potential Source ◽  
Northern United States

Strawberry transplants produced in nurseries across Canada, northern United States, and California are shipped annually to other strawberry-growing regions, including Florida. Botrytis cinerea, the causal agent of gray mold, causes latent infections on transplants which are suggested as a potential source of primary inoculum in strawberry fields. In this study, we investigated the survival of B. cinerea isolates over the summer in Florida, the presence of B. cinerea in transplants from 14 nurseries from Canada and the United States in 2011, 2012, and 2013, and the sensitivity of nursery population to several botryticides. Botrytis cinerea was detected on dead strawberry plants sampled from commercial strawberry fields between March and June but not in July and August, suggesting that the fungus does not over-summer in strawberry fields in Florida. Nursery transplants surveyed in 2011, 2012, and 2013 showed B. cinerea incidences of 20 to 37, 20 to 83, and 2.5 to 92.5%, respectively. In total, 409 isolates were tested for sensitivity to pyraclostrobin, boscalid, pyrimethanil, fenhexamid, iprodione, penthiopyrad, fluopyram, and fludioxonil. Overall, respective resistance frequencies were 91.7, 79.3, 33.2, 20.7, 2.4, 0.2, 0.2, and 0.0%. A majority of isolates tested were resistant to either 3 or 4 fungicides simultaneously. These findings reinforce the need for an integrated approach between strawberry nurseries and production fields to improve gray mold management and mitigate future risks of resistance development in B. cinerea.

Patterns of Insecticide Resistance in the Mosquitofish, Gambusia affinis

1969 ◽  
Vol 26 (9) ◽  
pp. 2395-2401 ◽  
Author(s):  
Dudley D. Culley Jr. ◽  
Denzel E. Ferguson
Keyword(s):  
Insecticide Resistance ◽  
High Resistance ◽  
Gambusia Affinis ◽  
Cross Resistance ◽  
Susceptible Population ◽  
State College ◽  
Resistant Population ◽  
Resistance Patterns ◽  
Population Patterns

The extent of insecticide resistance in a resistant population of mosquitofish (Gambusia affinis) from Belzoni, Mississippi, was compared with that of a susceptible population from State College, Mississippi, using 28 insecticides of five major groups. Results of 48-hr bioassays show that resistant mosquitofish have developed high resistance only to the toxaphene–endrin related insecticides, even though insecticides from other groups were heavily applied. Spray records for the Belzoni area and insecticide characteristics such as stability and toxicity aided in evaluating cross-resistance patterns in the resistant population. Patterns of resistance in mosquitofish are similar to those in many resistant arthropods.

scholarly journals Detection and Molecular Characterization of Resistance to the Dicarboximide and Benzamide Fungicides in Botrytis cinerea From Tomato in Hubei Province, China

Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1299-1306 ◽  
Author(s):  
M. Adnan ◽  
M. S. Hamada ◽  
G. Q. Li ◽  
C. X. Luo
Keyword(s):  
Botrytis Cinerea ◽  
Management Strategies ◽  
Resistance Management ◽  
Point Mutations ◽  
Hubei Province ◽  
Cross Resistance ◽  
Resistance Development ◽  
Fitness Parameters ◽  
The Mean

Altogether, 192 Botrytis cinerea isolates collected from tomato greenhouses at different locations in Hubei Province were evaluated for their sensitivity to fungicides procymidone and zoxamide. The mean effective concentration to cause 50% growth inhibition (EC50) values of procymidone for sensitive and resistant isolates were 0.25 and 3.60 μg/ml, respectively. The frequency of procymidone-resistant (ProR) isolates was 18%, and the highest frequency was recorded in Jingmen. Positive cross-resistance was observed for ProR isolates to other dicarboximide fungicides but not to phenylpyrroles. Significant differences were observed for fitness parameters (i.e., mycelial growth, osmotic sensitivity, and virulence between sensitive and resistant isolates). Amino acid sequence of the Bos1 gene revealed that ProR isolates carried either point mutations at codon 365 (I365S) or a pair of point mutations at codons 369 (Q369P) and 373 (N373S). For zoxamide, the mean EC50 values for sensitive and resistant isolates were 0.22 and 5.32 μg/ml, respectively. Approximately 14% of the isolates were found to be resistant to zoxamide, and the highest frequency of resistance was also observed in Jingmen. There was positive cross-resistance for zoxamide-resistant (ZoxR) isolates to carbendazim. No significant differences were observed for fitness parameters between zoxamide-sensitive and ZoxR isolates. Sequence analysis of the β-tubulin gene of Botrytis cinerea revealed two previously reported point mutations (E198A and E198K) and one new point mutation (T351I). This new mutation was detected in only those isolates which possessed the E198K but not E198A substitution. This study allows for a better understanding of the resistance development profile in Hubei Province. Results will be useful for the improvement of fungicide resistance management strategies.

scholarly journals Sensitivity of Botrytis cinerea to fungicides used in New Zealand wine grape spray programmes

2017 ◽  
Vol 70 ◽  
pp. 285-294
Author(s):  
R.M. Beresford ◽  
P.J. Wright ◽  
C.L. Middleditch ◽  
M. Vergara ◽  
L. Hasna ◽  
...  
Keyword(s):  
New Zealand ◽  
Botrytis Cinerea ◽  
High Sensitivity ◽  
Cross Resistance ◽  
Baseline Sensitivity ◽  
Resistance Development ◽  
Low Degree ◽  
Medium Resistance ◽  
Bunch Rot ◽  
Succinate Dehydrogenase Inhibitor

Fungicide resistance development in Botrytis cinerea threatens the efficacy of anilinopyrimidine (AP) fungicides, which have been used for botrytis bunch rot control in New Zealand vineyards for about 20 years. A 2016 survey of 33 vineyards in Gisborne, Hawke's Bay and Marlborough showed that the majority of 670 isolates tested in agar-based assays were sensitive to the AP cyprodinil (EC50 < 1 mg/litre), although 18% showed low-resistance (EC50 1-10 mg/litre) and 10% showed medium-resistance (EC50 >10 mg/litre). There was high cross-resistance to the APs cyprodinil and pyrimethanil. The survey also established baseline sensitivity to the succinate dehydrogenase inhibitor (SDHI) fungicide boscalid and >90% of isolates were sensitive (EC50 < 5 mg/litre). There was a low degree of cross-resistance between the SDHIs boscalid and fluopyram. There was also high sensitivity to fludioxonil (0.009 to 0.018 mg/litre) and to fenhexamid (0.49 to 0.76 mg/litre).

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