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 the in vitro germination and mycelial growth of Colletotrichum sp.

Design/methodology/approach: Effectiveness’ evaluation of each treatments was carried out using the methodology of poisoned cultures. The following concentrations were evaluated for hydrogen peroxide and potassium sorbate: 1.0, 0.8, 0.6, 0.4, 0.2, 0.16, 0.12, 0.08 and 0.04 %; for sodium bicarbonate: 1.0, 0.8, 0.6, 0.4 and 0.2 %; and finally for chitosan: 2.5, 2.0, 1.5, 1.0 and 0.5 %. A mycelial growth disc of Colletotrichum sp. six days old was placed on each poisoned culture. The experimental design to measure the inhibition of mycelial growth and conidia germination of Colletotrichum sp. was completely randomized with five replications. Results were analyzed with the Kruskal-Wallis test and average ranges were compared between them. The EC₅₀ and EC₉₅ of each product were determined by probit analyses.

Results: The hydrogen peroxide inhibits 100 % of mycelial growth from concentration of 0.16 %, while potassium sorbate from 0.2 %. Regarding to sodium bicarbonate and chitosan, they reached this effect in 1.0 and 2.5 %. Conidia germination was completely inhibited only with hydrogen peroxide and potassium sorbate. The EC₅₀ and EC₉₅ for hydrogen peroxide were 0.1 and 0.12 %, for potassium sorbate: 0.10 and 0.19 %, sodium bicarbonate: 0.16 and 0.88 %, and for chitosan: 1.20 and 2.18 %, respectively.

Findings/conclusions: The evaluated treatments represent an effective and viable ecological alternative for the control of Colletotrichum sp.