Inhibition of mycelial growth and conidium germination of Colletotrichum sp. for organic and inorganic products

Abstract

Objective: To evaluate the effect of hydrogen peroxide, potassium sorbate, sodium bicarbonate, and chitosan on mycelial growth and in vitro germination of Colletotrichum sp., to be used for future management of anthracnose disease in postharvest cv. Ataulfo mango fruit. Design/Methodology/Approach: The effectiveness of the treatments was evaluated using the poisoned culture method. The evaluated concentrations of hydrogen peroxide and potassium sorbate were 1.0, 0.8, 0.6, 0.4, 0.2, 0.16, 0.12, 0.08, and 0.04 %; sodium bicarbonate, 1.0, 0.8, 0.6, 0.4 and 0.2 %; and chitosan, 2.5, 2.0, 1.5, 1.0 and 0.5 %. A 6-day disk of Colletotrichum sp. mycelial growth was placed in each poisoned culture medium. The inhibition of mycelial growth and the germination of Colletotrichum sp. conidia were evaluated. The experimental design was completely randomized with five repetitions for mycelial growth and four for conidium germination. The results were analyzed using the Kruskal-Wallis test and the comparison of average ranges. The CE50 and CE95 of each product was estimated using Probit analysis with the results of mycelial growth inhibition. Results: The mycelial growth inhibition (100%) of the Colletotrichum sp. strain was reached starting at concentrations of 0.16, 0.2, 1.0, and 2.5% for hydrogen peroxide, potassium sorbate, sodium bicarbonate, and chitosan, respectively. The inhibition of conidium germination was only observed in treatments with hydrogen peroxide and potassium sorbate. The CE50 and CE95 for hydrogen peroxide was 0.1 and 0.12%; for potassium sorbate, 0.10 and 0.19%; for sodium bicarbonate, 0.16 and 0.88%; and for chitosan, 1.20 and 2.18%. Findings/Conclusions: The evaluated treatments represent an effective and viable ecological alternative for the control of Colletotrichum sp., causal agent of anthracnosis in mango fruit.