In vitro evaluation of fungicides and a natural cinnamon extract for the control of Rhizoctonia solani in Ullucus tuberosus

Centeno V.C.; Soto Y.R.N.; Meza R.M.M.; Estrada M.N. · Acta Agronomica (2025) · DOI: 10.15446/acag.v73n3.119320

Resumen

The evaluation of the efficacy of three fungicides: azoxystrobin, iprodione and carbendazim and a natural cinnamon extract against the fungus Rhizoctonia solani in Ullucus tuberosus was developed by preparing a homogeneous inoculum by mixing isolates from 3 producing locations, in order to represent the regional population of the pathogen under real conditions of mass storage. Ullucus tuberosus is a crucial crop for the food security of Andean communities in Peru. However, its production is often affected by post-harvest rot caused by Rhizoctonia solani, which leads to significant economic losses ranging from 20 % to 80 %, affecting the quality of the tubers, with visible deformations, rot, and cracks, that considerably reduce their commercial value. This study evaluated the effectiveness of different FRAC (Fungicide Resistance Action Committee) fungicides groups and a natural cinnamon extract in inhibiting the in vitro growth of R. solani on U. tuberosus tubers during the post-harvest period. Tubers were collected from 3 locations in Acobamba Province, Huancavelica, and incubated in humid chambers to induce R. solani sporulation. Treatments included azoxystrobin (QoI), iprodiona (Dicarboximides), and carbendazim (Benzimidazoles), as well as cinnamon extract, which was prepared by macerating crushed branches in distilled water at 60 °C for six hours. Eleven treatments were applied at low, medium, and high doses of each fungicide and extract, arranged in a completely randomized design (CRD) with six replicates. Antifungal efficacy was assessed based on the percentage of mycelial growth inhibition (PGI) on PDA (potato dextrose agar) media. According to the results, iprodione achieved 100 % inhibition of R. solani growth after 7 days, making it the most effective treatment, followed by azoxystrobin and cinnamon extract. These findings highlight the high efficacy of iprodione in controlling R. solani in O. tuberosus post-harvest, suggesting its application as a viable option for its management. © (2025), (Universidad Nacional de Colombia). All rights reserved.

Instituciones: Universidad Nacional de Huancavelica