In vitro mycelial sensitivity of Macrophomina phaseolina to fungicides

Abstract

Black root rot, caused by Macrophomina phaseolina (Tass.) Goid., is the most common root disease in soybean fields. This study aimed to determine the in vitro mycelial sensitivity, measured by the IC50 (concentration to inhibit 50% of the fungus mycelial growth) of a M. phaseolina isolate obtained from soybean, to different fungicides (thiram, iprodione, carbendazim, pyraclostrobin, fluquinconazol, tolyfluanid, metalaxyl and penflufen + trifloxystrobin), at six concentrations (0.01 mg L-1, 0.10 mg L-1, 1.00 mg L-1, 10.00 mg L-1, 20.00 mg L-1 and 40.00 mg L-1 of the active ingredient). The 0.00 mg L-1 concentration represented the control, without fungicide addition. The mycelial growth evaluation was performed with the aid of a digital pachymeter, by measuring the colonies diameter, when the fungus growth in the control treatment reached the Petri dish edge. The experimental design was completely randomized, with four replications. Concerning the fungitoxicity of active ingredients, a variation from non-toxic to highly fungitoxic was observed to the M. phaseolina isolate, with IC50 values ranging from 0.23 mg L-1 to > 40.00 mg L-1, being carbendazim the most efficient one (IC50 = 0.23 mg L-1). The fungus showed insensitivity to the active ingredients of fluquinconazole, metalaxyl, thiram and tolyfluanid.

Macrophomina phaseolina: General Characteristics of Pathogenicity and Methods of Control

“…As far as we know, no fungicides have been registered to control this pathogen. However, systemic and non-systemic fungicides (i.e., carbendazim, difenoconazole, benomyl, azoxystrobin, dazome) at different concentration were evaluated in vitro and in vivo against M. phaseolina (Cohen et al, 2012;Tonin et al, 2013;Chamorro et al, 2015a;Parmar et al, 2017;Lokesh et al, 2020).…”

Characterization of Five New Monosporascus Species: Adaptation to Environmental Factors, Pathogenicity to Cucurbits and Sensitivity to Fungicides

“…sensitivity to fungicides was measured by EC 50 , which is specific and constant for a given a.i. and pathogen, and a low EC 50 value represents a high fungicidal power [ 40 , 49 ]. All Monosporascus spp.…”

“…The effect of fungicides on mycelial growth of Monosporascus spp. was determined in vitro as described by Tonin et al [ 40 ]. The treatments included five a.i.—boscalid (Cantus WG, 50% a.i., systemic, BASF S.A.), carbendazim (Carbendazim, 99.9% a.i., systemic, Syngenta Proteção de Cultivos Ltd.a, Sao Paulo, Brazil), cyprodinil (Unix 750 WG, 75% a.i., systemic, Syngenta Proteção de Cultivos Ltd.a), fluazinam (Frowncide 500 SC, 50% a.i., contact, ISK Biosciences do Brasil Defensivos Agrícolas Ltd.a), and fludioxonil (Maxim, 25% a.i., contact, Syngenta Proteção de Cultivos Ltd.a)—and five concentration levels: 0.01, 0.1, 1, 10 and 100 mg/L a.i.…”

New isolates of Trichoderma antagonistic to Sclerotinia sclerotiorum

“…Radial mycelial growth of the pathogen (cm) was measured with the aid of a millimeter ruler and used for calculating inhibition of mycelial growth rate (Menten et al 1976) Comparison of means was performed using the Scott-Knott clustering test. The model residues were subjected to Box-Cox transformation when they had normal variance.…”