Control del moho azul en poscosecha de manzana con productos naturales

Spanish; Castilian. El uso de los extractos vegetales con actividad antimicrobiana para controlar enfermedades en pre o poscosecha es una alternativa promisoria frente al uso de fungicidas sintéticos. El objetivo de este estudio fue evaluar el efecto de extractos vegetales y aceites esenciales en manzanas infectadas naturalmente con Penicillium spp., agente causal del moho azul. Se sumergieron manzanas en extractos de cítricos y de neem (Azadirachta indica) en concentraciones de 0,5 y 1,0% (v/v) y se almacenaron a 25 °C y 90% de humedad relativa. Después de 21 días se midió incidencia y severidad de la enfermedad. También se evaluó el efecto de los aceites esenciales de Thymus vulgaris, Origanum vulgaris, Mentha piperita y Melaleuca alternifolia por fumigación. La fruta se almacenó a 25±2 °C y 90±5% de humedad relativa durante 21 días. Frutos tratados con agua destilada estéril constituyeron el tratamiento control. Los frutos sin tratar presentaron los valores más altos de incidencia (100%) y severidad (99,98%) de moho azul, así como el menor porcentaje de control (4,56%). Todos los tratamientos mostraron efecto antifúngico de Penicillium spp, sin embargo, los extractos cítricos y de A. indica en la concentración de 1,0% proporcionaron los mayores niveles de control de la enfermedad (99,57% y 98,33%, respectivamente). Los frutos tratados con aceites esenciales mostraron menor incidencia, menor severidad y mayor control de la enfermedad. Se ha demostrado que el extracto y aceites esenciales estudiados tienen actividad antifúngica y potencial para uso en poscosecha como una alternativa al control químico.

English. Plant extracts for the control of plant disease are emerging as promising alternatives to the use of synthetic fungicides. The objective of this work was to study the effect of plant extracts and essential oils on naturally infected apple fruits with Penicillium spp. causal agent of blue mold. Apple fruits were immersed in citric and Azadirachta indica extracts at concentrations of 0.5 and 1.0% (v/v), stored at room temperature (25 °C and 90% RH) and analyzed at 21 days after the application of the treatments. Evaluated also the effect of fumigation of apple fruits with essential oils of Thymus vulgaris, Origanum vulgaris, Mentha piperita and Melaleuca alternifolia. Treated fruits were stored at 25±2 °C and 90±5% relative humidity for 20 days. Treated fruit with distilled water constituted the group controls. The higher values of incidence (100%), severity (99.98%) and the lowest percentage of disease control (4.56%) were observed in apple fruits treated with distilled water (group control). All treatments exhibited inhibitory effect on Penicillium spp. in apple fruits, however, A. indica and citric extracts, at concentrations of 1.0%, had a disease control of98.33% and 99.57%, respectively. There were no significant differences between the oils applied; except between these and the control. However, the treatments with essential oils were that exhibited the least incidence, severity and control of the disease. The results showed that essential oils showed good results, above 98.1% of control of blue mold disease in postharvest. It was demonstrated that extracts the different concentration and essential oils have antifungal activities and that they have a potential use as an alternative control in relation to chemical methods.