Sensibilidad in vitro de Moniliophthora roreri H.C. Evans, agente causal de la moniliasis del cacao (Theobroma cacao L.) a fungicidas de diferentes modos de acción.

Abstract

The present investigation aimed to determine the in vitro sensitivity of Moniliophthora roreri, causal agent of cocoa moniliasis (Theobroma cacao L.), to fungicides of different modes of action, using six active ingredients: thiabendazole, tebuconazole, azoxystrobin, boscalid, copper sulfate and thyme plant extract. Eight strains of M. roreri from different places and genotypes in the province of Orellana were used. The stock solution of the fungicides was prepared from an initial concentration, serial dilutions were made to obtain the concentrations established in the investigation: 0.01, 0.1, 1, 1, 10 and 100 ppm, with these ones a solution was prepared with modified V8 culture medium and dispensed in Petri dishes with 3 replicates for each of the concentrations, except for the control in which only unamended medium was dispensed. Disks of M. roreri mycelial were grown and when the trial was carried out the growth of the fungus was evaluated with measurements every 48 hours. For statistical analysis, the R Studio program was used to determine the MGR and ED50 for each active principle. The results obtained were: thiabendazole (ED50: 19.25 - 109.09 ppm), tebuconazole (ED50: 0.007 - 0.114 ppm), azoxystrobin (ED50: 0.0008 - 0.020 ppm), boscalid (ED50: 0.14 - 0.57 ppm), copper sulfate (ED50: 63.38 - 203.35 ppm), plant extract (ED50: 1.66 ppm - 1757.52 ppm). It is concluded that the efficient active principles on M. roreri MGR were: tebuconazole, azoxystrobin and boscalid, on the other hand, the inefficient active principles were: thiabendazole, copper sulfate and vegetable extract. It is recommended to use tebuconazole, azoxystrobin and boscalid for the control of Moniliophthora roreri in the field in the different places from which the strains originate.