Inefficiency of capsaicin to inhibit in vitro Moniliophthora roreri Cif & Par, causal agent of Theobroma cacao L. moniliasis

Abstract

Objective: To evaluate in vitro the fungicidal efficiency of capsaicin to inhibit Moniliophthora roreri, causal agent of Theobroma cacao L. moniliasis.

Design / methodology / approach: Capsaicin reagent grade dissolved in absolute ethyl alcohol was used to prepare a stock solution of 2000 mg L^-1. Dilutions were prepared from this solution to obtain concentrations of 250, 500, 750 and 1000 mg L^-1. The efficacy on the inhibition of mycelial growth, sporulation and viability of conidia of M. roreri was evaluated with the plate dilution method. A completely randomized design (DCA) was established. The efficiency percentages were obtained by Abbott's formula (1925).

Results: The efficiency of capsaicin to inhibit mycelial growth of M. roreri was less than 15%. Likewise, it was inefficient in the inhibition of sporulation and spore viability (percentage of germination less than 5%). The efficiency of capsaicin in the inhibition of the mycelial development and the sporulation of M. roreri, is masked by the disinfecting action of the solvent from the concentration of 750 mgL^-1.

Limitations of the study / implications: The low efficiency of capsaicin to inhibit M. roreri requires the use of higher concentration solutions, always considering the solvent used as a comparative target.

Findings/conclusions: Capsaicin is ineffective in inhibiting the mycelial growth, sporulation and viability of M. roreri spores