Evaluación de la eficacia in vitro de fungicidas residuo cero sobre Cladosporium ramotenellum patógeno, asociado a la “mancha de hollín” en mandarina (Citrus reticulata), Cañete
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Date
2026-09-16
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Universidad Nacional de Cañete
Abstract
La “mancha de hollín” es una enfermedad de gran importancia económica en mandarinas (Citrus reticulata), debido a que provoca manchas oscuras superficiales, secas y firmes en la cascara del fruto, este daño es una infección latente que aparece en post cosecha. Los productos residuo cero tienen una creciente relevancia en cultivos de exportación debido a que generan acumulación de compuestos detectables en cromatografía, reduciendo el riesgo de rechazos en frontera. En esta investigación se evaluó la eficacia in vitro de fungicidas residuo cero sobre cepas de Cladosporium ramotenellum patógeno asociado a la “mancha de hollín” en mandarina (Citrus reticulata). Se utilizó bajo un diseño completo al azar (DCA) con 22 tratamientos (entre ellos de composición química, biológica y de extractos vegetales) más 1 testigo, con 3 repeticiones (placas) cada uno. Las variables evaluadas fueron: el crecimiento micelial de Cladosporium ramotenellum en presencia de extractos vegetales, químicos y biológicos, utilizando indicadores de tasa de crecimiento y diámetro de las colonias. Los tratamientos T15 (Jambo – Metabolitos bacterianos) y T20 (Luna tranquility), fueron los más eficaces, teniendo inhibición completa del crecimiento micelial durante los 20 días de evaluación sin registrar aumento en el diámetro de su colonia desde su inoculación. El T4 (Bacitab-s – Bacillus subtilis) presento un crecimiento micelial moderado durante los primeros días alcanzando una media de 17.83 mm de diámetro y a partir del día 10 detuvo el crecimiento por completo del patógeno, finalizando la investigación con 72.83% de inhibición. Los resultados en esta investigación muestran en promedio que los productos químicos logran un control rápido y elevado en los primeros días (4–6), aunque con una ligera reducción hacia el final del periodo evaluado. En contraste, los biológicos, pese a iniciar con eficacia moderada, incrementan progresivamente su acción alrededor del día 10 y alcanzando más del 80% de inhibición. Los extractos vegetales ofrecen un control inicial limitado pero constante, alcanzando un 65% de inhibición.
Sooty blotch is a disease that has a significant economic impact on late-season mandarins (Citrus reticulata) in the Lima and Ica regions, because it causes dark, dry, firm spots on the flavedo. This damage is a latent infection that appears after harvest, causing significant losses to producers as no symptoms are apparent at harvest time. As mandarins are an exportable fruit, chemical residues must be avoided prior to harvest. In view of this problem, zero-residue (organic-biological) products are promising targets for development. This research evaluated the in vitro efficacy of zero-residue fungicides on Cladosporium ramotenellum, a pathogen associated with “sooty blotch” in mandarins (Citrus reticulata). Using the poisoned food technique, the experiment was conducted under a completely randomized design (CRD) in the Plant Health Laboratory of the National University of Cañete. Twenty-two treatments (including chemical, biological, and plant extract compositions) plus one control were used, with three replicates (plates) each. The variables evaluated were: percentage of mycelial inhibition of Cladosporium ramotenellum, using growth rate and colony diameter indicators. The treatments T15 (Jambo – Bacterial metabolites) and T20 (Luna tranquility) were the most effective, completely inhibiting mycelial growth during the 20-day evaluation period without registering an increase in colony diameter since inoculation. T4 (Bacitab-s – Bacillus subtilis) showed moderate mycelial growth during the first few days, reaching an average diameter of 17.83 mm, and from day 10 onwards, it completely stopped the growth of the pathogen, ending the investigation with 72.83% inhibition. The results of this research show that, on average, chemical products achieve rapid and high control in the first few days (4–6), although with a slight reduction towards the end of the evaluation period. In contrast, biological products, despite starting with moderate efficacy, progressively increase their action around day 10, reaching more than 80% inhibition. Plant extracts offer limited but constant initial control, reaching 65% inhibition.
Sooty blotch is a disease that has a significant economic impact on late-season mandarins (Citrus reticulata) in the Lima and Ica regions, because it causes dark, dry, firm spots on the flavedo. This damage is a latent infection that appears after harvest, causing significant losses to producers as no symptoms are apparent at harvest time. As mandarins are an exportable fruit, chemical residues must be avoided prior to harvest. In view of this problem, zero-residue (organic-biological) products are promising targets for development. This research evaluated the in vitro efficacy of zero-residue fungicides on Cladosporium ramotenellum, a pathogen associated with “sooty blotch” in mandarins (Citrus reticulata). Using the poisoned food technique, the experiment was conducted under a completely randomized design (CRD) in the Plant Health Laboratory of the National University of Cañete. Twenty-two treatments (including chemical, biological, and plant extract compositions) plus one control were used, with three replicates (plates) each. The variables evaluated were: percentage of mycelial inhibition of Cladosporium ramotenellum, using growth rate and colony diameter indicators. The treatments T15 (Jambo – Bacterial metabolites) and T20 (Luna tranquility) were the most effective, completely inhibiting mycelial growth during the 20-day evaluation period without registering an increase in colony diameter since inoculation. T4 (Bacitab-s – Bacillus subtilis) showed moderate mycelial growth during the first few days, reaching an average diameter of 17.83 mm, and from day 10 onwards, it completely stopped the growth of the pathogen, ending the investigation with 72.83% inhibition. The results of this research show that, on average, chemical products achieve rapid and high control in the first few days (4–6), although with a slight reduction towards the end of the evaluation period. In contrast, biological products, despite starting with moderate efficacy, progressively increase their action around day 10, reaching more than 80% inhibition. Plant extracts offer limited but constant initial control, reaching 65% inhibition.
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Keywords
Fungicida residuo cero, in vitro, alimento envenenado, enfermedades post cosecha en cítricos.
Citation
Trujillo Quispe Estefanía, “Evaluación de la eficacia in vitro de fungicidas residuo cero sobre Cladosporium ramotenellum patógeno, asociado a la “mancha de hollín” en mandarina (Citrus reticulata), Cañete” , Tesis para optar el grado de Ingeniero Agronomo, Escuela de pregrado. Facultad de Ciencias Agrarias. Universidad Nacional de Cañete. Cañete - Perú