Minimum inhibitory concentration (MIC) and fungicide/fungistatic effect of eugenol, isoeugenol, carvacrol and thymol on Lasiodiplodia tehobromae isolated from vines with symptoms of grapevine wood decay in San Juan province.

ROSA MANZANO MELISA; SANTIAGO DANIEL PALMA; VARGAS PERRUCA MERCEDES; LOPEZ MARÍA L; PAPPANO DELIA; RAVETTI SOLEDAD; ACIAR ROXANA

San Luis

Otro; XXXVII Reunión Científica Anual. Sociedad de Biología de Cuyo.; 2019

Vine disease known as ?Grapevine wood decay? which is caused by ligninolytic fungi is internationally considered to have a greatimpact, as it causes the death of plants. The production of wine is the most important economic activity in the province of San Juan, so any pathology that alters the yield and quality of the vines have a strong economic impact. These pathologies are produced by a pool of ligninolytic fungi, which cause Eutypiosis, Esca, Petri Disease, BAD (Black Dead Arm), Malvón Leaf. Recently, Lasiodiplodia tehobromae has been reported as causative agent of irreversible destruction for the disease. We isolated the ligninolytic fungi from vine plants in San Juan. After morphological and molecular analyses, the presence of Lasiodiplodia tehobromae was confirmed. Minimum inhibitory concentrations (MIC) of Carvacrol, Thymol, Eugenol and Isoeugenol were determined through a bioassay using 5, 4, 3, 2.5, 2, 1.5, 1, 0.75 and 0.5 mM for each compound. Three replications of each treatment were performed. In order to evaluate if the compounds performed as fungicide or fungistatic agent, a subsequent bioassay was performed when absence of mycelium was detected in the MIC bioassay. It was obtained which MIC for Thymol, Carvacrol, Eugenol and Isoeugenol were 0.75, 0.75, 2.5, 3 mM respectively. Also, Thymol, Carvacrol, Eugenol and Isoeugenol were found to be fungicidal agents at 3, 3, 1 and higher than 5 mM respectively, according to visual inspection in the fungicide/fungistatic bioassay, demonstrating to be potential natural agents to continue their studies in the treatment of this disease.