Avaliação de compostos químicos sobre o crescimento micelial de Colletotrichum fructicola da mandioca (Manihot esculenta Crantz) in vitro

Abstract

Anthracnose of cassava (Colletotrichum spp.) is a highly destructive disease, especially under favorable environmental conditions and on susceptible hosts. Chemical control is among the most appropriate strategies for the management of this disease. Moreover, alternatives to control this pathogen through the use of compounds with fungicidal actions and capable of inducing systemic resistance mechanisms in plants are being sought. Therefore, the objective of this work was to evaluate the action of potassium phosphite and glycerol on the mycelial growth of C. fructicola. The experiment consisted in the evaluation in vitro of the mycelial growth of C. fructicola in an entirely randomized design, with seven treatments and six repetitions, as follows: negative control (water), three concentrations of glycerol (1%, 3% and 5%) and three concentrations of FITOATIV® potassium phosphite 28% P2O5 e 26% K2O(10ml/L, 30ml/L and 50ml/L). For the evaluation, the mycelial diameter (MD) was measured and later converted into percentage of mycelial growth inhibition (PMGI), followed by statistical analysis with Tukey's test (p<0.05). Potassium phosphite at 50 ml/L showed the best result, with PMGI of 56.30% (MD ≈ 39.33 mm), followed by 5% glycerol with the PMGI of 16.76% (MD ≈ 74.92 mm). Therefore, the results indicate that both compounds present potentials for control, however potassium phosphite (50ml/L), showed greater inhibition power on the mycelial growth of C. fructicola and indicate the need for further studies to evaluate the compounds in more concentrations and in pathogen-host interaction.