Discontinuance of tebuconazole in the field restores sensitivity of Monilinia fructicola in stone fruit orchards

2019 ◽  
Vol 69 (1) ◽  
pp. 68-76 ◽  
Author(s):  
W. V. Pereira ◽  
R. G. F. Morales ◽  
A. I. G. Bauer ◽  
K. Kudlawiec ◽  
L. L. May‐De‐Mio
Keyword(s):  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Fruit Orchards

scholarly journals Identification and Characterization of Benzimidazole Resistance in Monilinia fructicola from Stone Fruit Orchards in California

2003 ◽  
Vol 69 (12) ◽  
pp. 7145-7152 ◽  
Author(s):  
Zhonghua Ma ◽  
Michael A. Yoshimura ◽  
Themis J. Michailides
Keyword(s):  
Dna Sequences ◽  
Point Mutations ◽  
Brown Rot ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Tubulin Gene ◽  
Benzimidazole Fungicides ◽  
Specific Pcr ◽  
Allele Specific ◽  
Fruit Orchards

ABSTRACT Low and high levels of resistance to the benzimidazole fungicides benomyl and thiophanate-methyl were observed in field isolates of Monilinia fructicola, which is the causative agent of brown rot of stone fruit. Isolates that had low levels of resistance (hereafter referred to as LR isolates) and high levels of resistance (hereafter referred to as HR isolates) were also cold and heat sensitive, respectively. Results from microsatellite DNA fingerprints showed that genetic identities among the populations of sensitive (S), LR, and HR isolates were very high (>0.96). Analysis of DNA sequences of theβ -tubulin gene showed that the LR isolates had a point mutation at codon 6, causing a replacement of the amino acid histidine by tyrosine. Codon 198, which encodes a glutamic acid in S and LR isolates, was converted to a codon for alanine in HR isolates. Based on these point mutations in the β-tubulin gene, allele-specific PCR assays were developed for rapid detection of benzimidazole-resistant isolates of M. fructicola from stone fruit.

scholarly journals Co-Infection with Three Mycoviruses Stimulates Growth of a Monilinia fructicola Isolate on Nutrient Medium, but Does Not Induce Hypervirulence in a Natural Host

Viruses ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 89 ◽  
Author(s):  
Thao Tran ◽  
Hua Li ◽  
Duy Nguyen ◽  
Michael Jones ◽  
Stephen Wylie
Keyword(s):  
Inhibitory Effect ◽  
Fungal Species ◽  
Natural Host ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Isogenic Lines ◽  
Nutrient Agar Medium ◽  
Fruit Orchards ◽  
Hyphal Tip

Monilinia fructicola and Monilinia laxa are the most destructive fungal species infecting stone fruit (Prunus species). High-throughput cDNA sequencing of M. laxa and M. fructicola isolates collected from stone fruit orchards revealed that 14% of isolates were infected with one or more of three mycoviruses: Sclerotinia sclerotiorum hypovirus 2 (SsHV2, genus Hypovirus), Fusarium poae virus 1 (FPV1, genus Betapartitivirus), and Botrytis virus F (BVF, genus Mycoflexivirus). Isolate M196 of M. fructicola was co-infected with all three viruses, and this isolate was studied further. Several methods were applied to cure M196 of one or more mycoviruses. Of these treatments, hyphal tip culture either alone or in combination with antibiotic treatment generated isogenic lines free of one or more mycoviruses. When isogenic fungal lines were cultured on nutrient agar medium in vitro, the triple mycovirus-infected parent isolate M196 grew 10% faster than any of the virus-cured isogenic lines. BVF had a slight inhibitory effect on growth, and FPV1 did not influence growth. Surprisingly, after inoculation to fruits of sweet cherry, there were no significance differences in disease progression between isogenic lines, suggesting that these mycoviruses did not influence the virulence of M. fructicola on a natural host.

scholarly journals Field Strains of Monilinia fructicola Resistant to Both MBC and DMI Fungicides Isolated from Stone Fruit Orchards in the Eastern United States

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1063-1068 ◽  
Author(s):  
F. Chen ◽  
X. Liu ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
Sweet Cherry ◽  
Management Strategies ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Eastern United States ◽  
Peach Fruit ◽  
Thiophanate Methyl ◽  
Dmi Fungicides ◽  
Fruit Orchards

In 2012, significant brown rot disease was observed on stone fruit in Pennsylvania, Maryland, and South Carolina despite preharvest application of methyl benzimidazole carbamate (MBC) and demethylase inhibitor (DMI) fungicides. In total, 140 Monilinia fructicola isolates were collected from diseased orchards and examined for fungicide sensitivity. In addition to isolates resistant to either the DMI propiconazole or the MBC thiophanate-methyl, 22 isolates were discovered that were resistant to both fungicides, including 4 isolates from peach in South Carolina, 12 isolates from peach and sweet cherry in Maryland, and 6 isolates from sweet cherry in Pennsylvania. Analysis of MBC resistance revealed that dual-resistant isolates from South Carolina carried the β-tubulin E198A mutation, whereas isolates from Maryland and Pennsylvania carried E198 mutations not previously described in the Monilinia genus, E198Q or F200Y. The genetic element Mona, associated with DMI fungicide resistance in M. fructicola, was detected in the dual-resistant isolates from South Carolina but not in the isolates from the two more northern states. An investigation into the molecular mechanism of DMI resistance in the latter isolates revealed that resistance was not based on increased expression or mutation of MfCYP51, which encodes the target of DMI fungicides. Label rates of formulated propiconazole or thiophanate-methyl were unable to control dual-resistant isolates on detached peach fruit, confirming field relevance of dual resistance. The same isolates were not affected by fitness penalties based on mycelial growth rate, ability to sporulate, and virulence on detached peach fruit. The emergence of M. fructicola strains resistant to both DMI and MBC fungicides in multiple states and multiple stone fruit crops is a significant development and needs to be considered when designing resistance management strategies in stone fruit orchards.

Quantification of airborne spores of Monilinia fructicola in stone fruit orchards of California using real-time PCR

2007 ◽  
Vol 118 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Y. Luo ◽  
Z. Ma ◽  
H. C. Reyes ◽  
D. Morgan ◽  
T. J. Michailides
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Airborne Spores ◽  
Fruit Orchards

scholarly journals Cross-Resistance Among Demethylation Inhibitor Fungicides With Brazilian Monilinia fructicola Isolates as a Foundation to Discuss Brown Rot Control in Stone Fruit

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2843-2850
Author(s):  
Pamela Suellen Salvador Dutra ◽  
Paulo S. F. Lichtemberg ◽  
Maria Bernat Martinez ◽  
Themis J. Michailides ◽  
Louise Larissa May De Mio
Keyword(s):  
Brown Rot ◽  
Lesion Size ◽  
Stone Fruit ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Wild Type ◽  
Specific Test ◽  
Allele Specific ◽  
Fruit Orchards ◽  
Demethylation Inhibitor

Despite the resistance problems in Monilinia fructicola, demethylation inhibitor fungicides (DMIs) are still effective for the disease management of brown rot in commercial stone fruit orchards in Brazil. This study aims to investigate the sensitivity of M. fructicola isolates and efficiency of DMIs to reduce brown rot. A set of 93 isolates collected from Brazilian commercial orchards were tested for their sensitivities to tebuconazole, propiconazole, prothioconazole, and myclobutanil. The isolates were analyzed separately according to the presence or absence of the G461S mutation in MfCYP51 gene, determined by allele-specific test. The mean EC50 values for G461S mutants and wild-type isolates were respectively 8.443 and 1.13 µg/ml for myclobutanil, 0.236 and 0.026 µg/ml for propiconazole, 0.115 and 0.002 µg/ml for prothioconazole, and 1.482 and 0.096 µg/ml for tebuconazole. The density distribution curves of DMI sensitivity for both genotypes showed that myclobutanil and prothioconazole curves were mostly shifted toward resistance and sensitivity, respectively. Incomplete cross-resistance was detected among propiconazole and tebuconazole in both wild-type (r = 0.45) and G461S (r = 0.38) populations. No cross-sensitivity was observed among wild-type isolates to prothioconazole and the others DMIs tested. Fungicide treatments on detached fruit inoculated with M. fructicola genotypes showed significant DMI efficacy differences when fruit were inoculated with wild-type and G461S isolates. Protective applications with prothioconazole were more effective for control of both G461S and wild-type isolates compared with tebuconazole. Curative applications with tebuconazole were most effective in reducing the incidence and lesion size of G461S isolates. Sporulation occurred only for G461S isolates treated with tebuconazole under curative and preventative treatments. The differences found among the performance of triazoles against M. fructicola isolates will form the basis for recommendations of rational DMI usage to control brown rot in Brazil.

Monilinia fructicola and Monilinia laxa isolates from stone fruit orchards sprayed with fungicides displayed a broader range of responses to fungicides than those from unsprayed orchards

2018 ◽  
Vol 153 (4) ◽  
pp. 985-999 ◽  
Author(s):  
T. T. Tran ◽  
Hua Li ◽  
D. Q. Nguyen ◽  
M. G. K. Jones ◽  
K. Sivasithamparam ◽  
...  
Keyword(s):  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Monilinia Laxa ◽  
Fruit Orchards

scholarly journals Significance of Thinned Fruit as a Source of the Secondary Inoculum of Monilinia fructicola in California Nectarine Orchards

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 519-524 ◽  
Author(s):  
Chuanxue Hong ◽  
Brent A. Holtz ◽  
David P. Morgan ◽  
Themis J. Michailides
Keyword(s):  
Brown Rot ◽  
Weather Conditions ◽  
San Joaquin Valley ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Inoculum Source ◽  
Secondary Infections ◽  
Fruit Orchards ◽  
Semi Arid

The significance of thinned fruit as a source of secondary inoculum in the spread of brown rot, caused by Monilinia fructicola, under semi-arid weather conditions of the San Joaquin Valley in California, was investigated in seven nectarine orchards in 1995 and 1996. Between 6 and 60% (depending on the orchard) of thinned fruit showed sporulation by M. fructicola. Brown rot was significantly less severe at preharvest (five orchards) and postharvest (one orchard) on fruit harvested from trees in plots from which thinned fruit were completely removed than on those in plots from which thinned fruit were not removed. M. fructicola sporulated more frequently on thinned fruit placed into irrigation trenches than on those left on the dry berms in tree rows. The incidence of preharvest fruit brown rot increased exponentially as the density of thinned fruit increased on the orchard floor. These results suggest that thinned fruit left on the floor of nectarine orchards can be a significant inoculum source of secondary infections. Removal or destruction of thinned fruit should reduce brown rot in nectarine and possibly other stone fruit orchards under semi-arid California conditions.

Overwintering of Monilinia fructicola in Stone Fruit Orchards in Northern China

2008 ◽  
Vol 156 (4) ◽  
pp. 229-235 ◽  
Author(s):  
Y. F. Zhong ◽  
Y. W. Zhang ◽  
X. Y. Chen ◽  
Y. Luo ◽  
L.Y. Guo
Keyword(s):  
Northern China ◽  
Stone Fruit ◽  
Monilinia Fructicola ◽  
Fruit Orchards
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