Nondestructive Sampling to Monitor <i>Macrophomina phaseolina</i> Root Colonization in Overwintering Stevia

Rogers, Layne W.; Koehler, Alyssa

doi:10.1094/php-10-20-0092-br

Cited by 2 publications

(2 citation statements)

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“…This particular study did not study the effect of soil disinfestation over several years of production. Therefore, long-term studies are needed to evaluate the year-to-year impacts of ASD in stevia [81].…”

Section: Effectiveness Of Integrating Asd and Fungicide Programs Unde...mentioning

confidence: 99%

Integrated Pathogen Management in Stevia Using Anaerobic Soil Disinfestation Combined with Different Fungicide Programs in USA, Mexico, and Paraguay

et al. 2023

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Stevia is a semi-perennial crop grown to obtain the diterpene glycosides in its leaves, which are processed to manufacture non-caloric sweeteners. Anaerobic soil disinfestation (ASD) and fungicide application were evaluated for the management of stevia stem rot (SSR) and Septoria leaf spot (SLS) in lab and field experiments. In 2019 and 2021, experiments using carbon sources for ASD were carried out in microplots at NCSU (Clayton, NC, USA). In 2020/21 and 2021/22 seasons, field experiments were conducted at CSAEGRO, Mexico (MX) and CEDIT, Paraguay (PY) using a 2 × 3 factorial design with two ASD treatments and three fungicide treatments. ASD treatments included soil amended with cornmeal (MX) or wheat bran (PY) at a rate of 20.2 Mg ha−1, molasses at 10.1 Mg ha−1, and non-amended controls. Fungicide applications included chemical (azoxystrobin), organic (pyroligneous acid, PA), and a non-treated control. ASD was effective in reducing sclerotia viability of Sclerotium rolfsii in laboratory assays (p < 0.0001) and microplot trials (p < 0.0001) in NC. During field trials, the viability of sclerotia was significantly reduced (p < 0.0001) in soils amended with cornmeal + molasses or wheat bran + molasses as carbon sources for ASD. While there was no significant effectiveness of ASD in reducing SLS in 2020 and 2021 or SSR in MX 2020 field trials (p = 0.83), it did exhibit efficacy on SSR in 2021 (p < 0.001). The application of fungicides was significantly effective in reducing SSR (p = 0.01) and SLS (p = 0.001), with azoxystrobin being the most consistent and PA not being statistically different from the control or azoxystrobin. The effects of ASD on fresh yield were inconsistent, exhibiting significant effects in Mexican fields in 2020 but not in 2021. During Paraguayan field trials, ASD only significantly interacted with fungicide applications in the dry yield in 2022. In the 2020/21 MX and 2020 PY field trials, fungicides were significantly effective in enhancing dry leaf yields, with azoxystrobin showing the highest consistency among treatments and PA variable control. In conclusion, utilizing ASD alongside organic fungicides can be a valuable tool for stevia farmers when the use of chemical fungicides is limited. Further research is required to enhance consistency and reduce the costs associated with these treatments under diverse edaphoclimatic conditions.

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Section: Effectiveness Of Integrating Asd and Fungicide Programs Unde...mentioning

confidence: 99%

Integrated Pathogen Management in Stevia Using Anaerobic Soil Disinfestation Combined with Different Fungicide Programs in USA, Mexico, and Paraguay

et al. 2023

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“…is caused by the ubiquitous soilborne fungus Macrophomina phaseolina (Tassi) Goid. M. phaseolina infects a wide range of plant hosts and is distributed worldwide [ 1 , 2 , 3 , 4 , 5 ]. Under favorable environmental conditions, host infection begins with the germination of microscelerotia in the soil near plant roots.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Role of Exogenously Applied Ascorbic Acid in Rescuing Soybean Plant Health in The Presence of Pathogen-Induced Oxidative Stress

Noor

Little

2022

Pathogens

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Charcoal rot, caused by the soilborne hemibiotrophic fungus Macrophomina phaseolina, is a prevalent and economically significant plant disease. It is hypothesized that M. phaseolina induces oxidative stress-mediated senescence in plants. Infection by M. phaseolina results in the host’s accumulation of reactive oxygen species (ROS) that contribute toward basal defense. However, the production of ROS could also lead to cellular damage and senescence in host tissue. This study aimed to determine if ascorbic acid, a ROS scavenging molecule, could quench M. phaseolina-induced hydrogen peroxide (H2O2) generation in a soybean-M. phaseolina pathosystem. In vitro sensitivity tests showed that M. phaseolina isolates were sensitive to L-ascorbic acid (LAA) at concentrations of 10.5 to 14.3 mM based on IC50 (half-maximal inhibitory concentration) data. In planta cut-stem assays demonstrated that pre-treatment with 10 mM of either LAA (reduced form) or DHAA (dehydroascorbic acid; oxidized form) significantly decreased lesion length compared to the non-pretreated control and post-treatments with both ascorbic acid forms after M. phaseolina inoculation. Further, H2O2 quantification from ascorbic acid-pretreated tissue followed by M. phaseolina inoculation showed significantly less accumulation of H2O2 than the inoculated control or the mock-inoculated control. This result demonstrated that M. phaseolina not only induced H2O2 after host infection but also increased ROS-mediated senescence. This study shows the potential of ascorbic acid, an effective ROS scavenger, to limit ROS-mediated senescence associated with M. phaseolina infection.

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Nondestructive Sampling to Monitor Macrophomina phaseolina Root Colonization in Overwintering Stevia

Cited by 2 publications

References 5 publications

Integrated Pathogen Management in Stevia Using Anaerobic Soil Disinfestation Combined with Different Fungicide Programs in USA, Mexico, and Paraguay

Integrated Pathogen Management in Stevia Using Anaerobic Soil Disinfestation Combined with Different Fungicide Programs in USA, Mexico, and Paraguay

Evaluating the Role of Exogenously Applied Ascorbic Acid in Rescuing Soybean Plant Health in The Presence of Pathogen-Induced Oxidative Stress

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