Anaerobic Soil Disinfestation Reduces Germination and Affects Colonization of Sclerotium rolfsii Sclerotia

Abstract

Growth chamber and field studies were conducted with organic amendment mixtures of carbon (C) and nitrogen (N) at C:N ratios 10:1, 20:1, 30:1, and 40:1 and amendment rates of C at 2, 4, 6, and 8 mg/g of soil (C:N ratio 30:1) to evaluate anaerobic soil disinfestation (ASD) effects on germination and colonization of Sclerotium rolfsii. In the growth chamber, sclerotial germination was reduced in all ASD treatments regardless of C:N ratio (0.6 to 8.5% germination) or amendment rate (7.5 to 46%) as compared with nonamended controls (21 to 36% and 61 to 96%, respectively). ASD treatment increased Trichoderma spp. colonization of sclerotia, with consistently higher colonization in ASD treatments with amendment rates of C at 2 or 4 mg/g of soil (>87% colonization) compared with nonamended controls (<50% colonization). In the 2014 field study, sclerotial germination was reduced by 24 to 30% in ASD treatments when compared with the nonamended control. Sclerotial colonization by Trichoderma spp. was predominant; however, other potential mycoparasites (i.e., Aspergillus spp., Fusarium spp., zygomycetes, and other fungi) were present in the field study. Amendment C:N ratios in the range of 10:1 to 40:1 were equally effective in reducing sclerotial germination and enhancing colonization by potentially beneficial mycoparasites of sclerotia.

Carbon source dependent-anaerobic soil disinfestation (ASD) mitigates the sclerotial germination of Sclerotinia sclerotiorum

“…We also found that C source amended treatments should be maintained under anaerobic conditions to achieve the best results compared to the C source amended aerobic treatments. According to our knowledge, with the exception of the present research, ASD has never been tested against S. sclerotiorum in Sri Lanka and only few attempts have made in the USA (Butler et al 2014;Sanabria-Velazquez et al, 2018) although it is well tested against many other soil borne pathogens around the world (Blok et al 2000;Goud et al 2004;Hewavitharana and Mazzola 2016;Kokalis-Burelle et al 2013;Momma 2008;Shrestha et al 2018). Though durian and grass cuttings did not completely inhibited sclerotia germination, they were effective compared to the aerobic negative control.…”

“…It has been found to be effective in suppressing numerous soil borne plant pathogens including Fusarium oxysporum f. sp. cubense (FOC) (Wen et al 2015), Rhizoctonia solani AG-5 and Pratylenchus penetrans (Hewavitharana and Mazzola 2016), Meloidogyne arenaria, M. incognita and M. javanica (Kokalis-Burelle et al 2013) Phytophthora nicotianae (Serrano-Pérez et al 2017), and Sclerotium rolfsii (Shrestha et al 2018). Interestingly it has been found that the suppression depends on the C source added.…”

Production of β-1,3-glucanase and chitosanase from clostridial strains isolated from the soil subjected to biological disinfestation

“…During the treatment, anoxic conditions in the soil are maintained with rather higher temperature (around 30 °C) under the sunlight. Effectiveness of BSD treatments to kill or inactivate many kinds of soil-borne plant pathogens has been demonstrated (Browne et al 2018; Butler et al 2014; Huang et al 2016; Mazzola et al 2018; Meng et al 2018; Messiha et al 2007; Muramoto et al 2014; Serrano-Pérez et al 2017; Shennan et al 2018; Shrestha et al 2018). Mowlick et al (2012, 2013a, b, c, 2014) reported that obligate anaerobic bacteria, mainly various linages from the class Clostridia , proliferate in the soil under such treatments.…”

β-1,3-Glucanase production as an anti-fungal enzyme by phylogenetically different strains of the genus Clostridium isolated from anoxic soil that underwent biological disinfestation

“…BSD is also referred to as reductive or anaerobic soil disinfestation (RSD or ASD), as the development of reductive or anaerobic conditions of the soil during treatment is essential for successful elimination of the pathogens (Blok et al 2000;Goud et al 2004;Momma 2008;Momma et al 2013;Strauss and Kluepfel 2015). The effectiveness of the method in suppressing soil-borne plant pathogens has been reported for various crops and plant diseases in different regions of the world (Browne et al 2018;Butler et al 2014;Huang et al 2016;Mazzola et al 2018;Meng et al 2018;Messiha et al 2007;Muramoto et al 2014;Serrano-Pérez et al 2017;Shennan et al 2018;Shrestha et al 2018). In this method, organic matter (usually plant biomass) needs to first be incorporated into the soil of the fields with irrigation water for moisture saturation.…”