Diagrammatic scale for assessing foliar symptoms of alternaria brown spot in citrus

Martelli, Ivan Bortolato; Pacheco, Camilla de Andrade; Bastianel, Marinês; Schinor, Evandro Henrique; Conceição, Patrícia Marluci da; Azevedo, Fernando Alves de

doi:10.33158/asb.2016v2i2p57

Cited by 9 publications

(7 citation statements)

References 8 publications

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“…The trial was conducted in 2021 in an entirely randomized design with a 2x3 factorial scheme, with two control methods (preventive and curative) and three replicates per concentration. The experiment was set up according to the in vitro severity assessment model of Azevedo et al ( 4) using the diagrammatic assessment scale of Martelli et al (18).…”

Section: Preventive and Curative Control On Detached Leavesmentioning

confidence: 99%

Citrus Essential Oils as an Alternative Method of Control of the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Azevedo¹,

Devite²,

Bastianel³

et al. 2023

Preprint

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Alternaria brown spot (ABS) is a disease caused by the fungus Alternaria alternata f. sp. citri, which results in lesions on fruits, leaves, and branches of several mandarin varieties and their hybrids. Due to the high cost of fungicide application, alternative methods for controlling ABS need to be studied. Therefore, this study aimed to evaluate the use of essential oils (EOs) from different mandarin varieties to mitigate the effects of ABS. The inhibitory effect of different concentrations (1, 2, 4, 8, and 16 μL mL-1) of Fremont IAC 543 mandarin, IAC 2019Maria mandarin, Murcott IAC 221 tangor, and Late IAC 855 willowleaf. EOs on the in vitro mycelial growth of the fungus A. alternata was evaluated. Additionally, the curative and preventive effects of these EOs on ABS symptoms on detached leaves of Murcott IAC 221 tangor were also assessed. The EO of IAC 2019Maria mandarin induced less mycelial growth, and consequently, greater inhibition of the growth of the fungus A. alternata at a concentration of 16 μL mL-1. This EO was more effective in control than the other oils tested. In the detached leaf experiment, both the curative and preventive treatments at a concentration of 16 μL mL-1 showed lower values of disease severity.

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Section: Preventive and Curative Control On Detached Leavesmentioning

confidence: 99%

Citrus Essential Oils as an Alternative Method of Control of the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Azevedo¹,

Devite²,

Bastianel³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…The trial was conducted in 2021 in an entirely randomized design, with a 2 × 3 factorial scheme, two control methods (preventive and curative), and three replicates with three leaves each per concentration. The experiment was set up according to the in vitro severity assessment model [4], using the diagrammatic assessment scale [21].…”

Section: Preventive and Curative Control On Detached Leavesmentioning

confidence: 99%

“…where, Pi = percentage of growth inhibition dc = the mean diameter of the colony of the fungus in the control dt = the mean diameter of the fungus colony in the treatment The assessment of the lesions on the detached leaves caused by the fungus was performed seven days after inoculation by observing the typical symptoms of the disease and subsequently determining the injured area (% of leaf taken by the disease), as described by Martelli et al [21]. This represented the levels of symptoms in ten illustrated grades, where "0" represented a leaf without symptoms and the severity grades ranged from 0.3 to 97% of the leaf area affected by A. alternata symptoms.…”

Section: Assessments and Data Analysismentioning

confidence: 99%

Mandarin Essential Oils as an Alternative Method of Controlling the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Devite¹,

Azevedo²,

Bastianel³

et al. 2023

Horticulturae

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Alternaria brown spot (ABS) is a disease caused by the fungus A. alternata f. sp. citri, which results in lesions on the fruits, leaves, and branches of several mandarin varieties and their hybrids. Due to the high cost of fungicide application, alternative methods for controlling ABS need to be studied. Therefore, this study aimed to evaluate the use of essential oils (EOs) from different mandarin varieties to mitigate the effects of ABS. The inhibitory effect of different concentrations (1, 2, 4, 8, and 16 μL·mL−1) of the EOs of Fremont IAC 543 mandarin, IAC 2019Maria mandarin, Murcott IAC 221 tangor, and Late IAC 855 willowleaf on the in vitro mycelial growth of the fungus A. alternata was evaluated. Additionally, the curative and preventive effects of these EOs on the ABS symptoms in detached leaves of Murcott IAC 221 tangor were also assessed. The EO of IAC 2019 Maria mandarin induced less mycelial growth, and consequently, a greater inhibition of the growth of the fungus A. alternata at a concentration of 16 μL·mL−1. This EO was more effective for control than the other oils tested. In the detached leaf experiment, both the curative and preventive treatments at a concentration of 16 μL·mL−1 showed lower values of disease severity.

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“…Petri dishes were kept in BOD incubator chamber at temperature of 27°C and 12-hour photoperiod. Disease evaluations were performed 24, 48 and 72 hours after inoculation, using the diagrammatic scale described by Martelli et al (2016).…”

Section: In Vitro Inoculation and Evaluation Of Symptomsmentioning

confidence: 99%

Response of citrus hybrids to Alternaria alternata inoculation

et al. 2020

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Citrus orchards have some limitations, such as the occurrence of phytosanitary problems. Alternaria brown spot (ABS) is caused by fungus Alternaria alternata, which affects several parts of the plant by producing a host-specific toxin, known as ACT. ABS is a limiting factor in orchards due to the susceptibility of most planted cultivars: ‘Murcott’ tangor and ‘Ponkan’ tangerine. The selection of varieties resistant/tolerant to the disease has economic importance. Therefore, the aim of this experiment was to evaluate the response to A. alternata inoculation in a population of ‘Murcott’ tangor vs ‘Pera’ sweet orange hybrids. Leaves of 2-3 centimeters in length of ‘Murcott’ tangor, ‘Pera’ sweet orange, ‘Ponkan’, ‘Dancy’, ‘Fremont’ tangerine and 198 hybrids were collected. For in vitro inoculation, monosporic A. alternata culture at concentration of 105 conidia mL-1 was used. Inoculated leaves were stored in humid chamber. After 24, 48 and 72 hours of inoculation, leaf lesions were evaluated following a diagrammatic scale. The results obtained showed that most hybrids from the crossing of ‘Murcott’ tangor vs ‘Pera’ sweet orange are susceptible to ABS. However, 44 are resistant and ten are tolerant. Among ABS-tolerant hybrids, some have phenotype similar to that of cultivated and commercialized hybrids.

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Diagrammatic scale for assessing foliar symptoms of alternaria brown spot in citrus

Cited by 9 publications

References 8 publications

Citrus Essential Oils as an Alternative Method of Control of the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Citrus Essential Oils as an Alternative Method of Control of the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Mandarin Essential Oils as an Alternative Method of Controlling the Fungus Alternaria alternata (Fr.: Fr.) Keissler

Response of citrus hybrids to Alternaria alternata inoculation

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