The Effect of Fungicides on Mycelial Growth and Conidial Germination of the Ginseng Root Rot Fungus, Cylindrocarpon destructans

Abstract

Ginseng root rot caused by Cylindrocarpon destructans is the most destructive disease of ginseng. Six different fungicides (thiophanate-methyl, benomyl, prochloraz, mancozeb, azoxystrobin, and iprodione) were selected to evaluate the inhibitory effect on the mycelial growth and conidial germination of C. destructans isolates. Benomyl and prochloraz were found to be the most effective fungicides in inhibiting mycelial growth of all tested isolates, showing 64.7% to 100% inhibition at a concentration of 10 µg/mL, whereas thiophanate-methyl was the least effective fungicide, showing less than 50% inhibition even at a higher concentration of 100 µg/mL. The tested fungicides exhibited less than 20% inhibition of conidium germination at concentrations of 0.01, 0.1, and 1 µg/mL. However, the inhibition effect of mancozeb on condium germination of C. destructans was significantly increased to 92% to 99% at a higher concentration of 100 µg/mL, while the others still showed no higher than 30% inhibition.

Inhibitory Properties of Aldehydes and Related Compounds against Phytophthora infestans—Identification of a New Lead

“…Mancozeb inhibited P. infestans growth most effectively, with an MIC of 100 μM and an IC 50 of between 25 and 50 μM. These MIC and IC 50 values for Mancozeb are similar to those reported previously for P. infestans , other oomycetes and in the fungus Cylindrocarpon destructans [ 10 , 46 ]. Based on these findings, we selected a fixed concentration of 25 μM to screen compounds for their ability to inhibit P. infestans growth (in order to identify molecules that are more effective than Mancozeb), with 1 mM cinnamaldehyde and 100 μM Mancozeb in positive control experiments.…”

Synthesis and Evaluation of Novel Ellipticines and Derivatives as Inhibitors of Phytophthora infestans

“…Nineteen synthetic ellipticine derivatives were assessed in a parallel approach, via the determination of inhibitory effects on the mycelial growth, zoosporogenesis and zoospore motility in Phytophthora infestans and cytotoxicity against a mammalian cell-line, human embryonic kidney-293T (HEK-293T) and all data reported is the mean of three individual experiments [ 38 , 39 , 40 , 41 , 42 ].…”

“…Cinnamaldehyde was used for comparison at a concentration of 1 mM; however, the active concentration of cinnamaldehyde was determined by Hu et al to be 2 mM to completely inhibit mycelial growth [ 38 ]. Mancozeb 1 , a commercial pesticide, was also tested at 100 μM as this was found to be the active anti-oomycete concentration by Shin et al [ 40 ].…”

Metabolomic Profiling of Fungal Pathogens Responsible for Root Rot in American Ginseng

“…Root rot is the primary concern for ginseng farmers; it can infect ginseng plants at any stage of growth, making it difficult to control [8,9]. Because of its persistence and virulence, root rot is a contributor to ginseng replant disease, another major concern for ginseng farmers [10]. Replant disease occurs when ginseng planted in the same soil as a previous ginseng crop fails to grow.…”