In vitro evaluation of commercial fungicides for control of Colletotrichum spp., in blackberry

Abstract

Efficiency in vitro of five chemical fungicides, three plant extracts and three biocontrol products were evaluated by their inhibition of mycelial growth percentage and inhibition of fungal biomass percentage, for Colletotrichum gloeosporioides strain 52 and Colletotrichum acutatum strain 168. In the group of chemical fungicides, the best results for inhibition of mycelial growth of both pathogens were obtained with Copper Hydroxide and Difenoconazole, showing 100% of inhibition. Regarding biomass inhibition, the products with higher inhibitory effect in C. gloeosporioides were Difenoconazole showing 100% of inhibition, and Benomyl, which inhibition was between 93% and 99%, and in C. acutatum was Difenoconazol with 100% inhibition and Azoxystrobin with an inhibition between 91% and 97%. Regarding the plant extracts group, Citrus sinensis and C. grandis composed extract, showed 100% inhibition of mycelial growth and fungal biomass, it was the most effective for controlling both strains of fungi. In the biocontrol products group, the inhibition of mycelial growth percentage of the based products on Trichoderma lignorum and T. harzianum was between 61% and 65% for C. gloeosporioides, and between 77% and 79% in C. acutatum, considered in the group of biocontrol products as the most efficient in the in vitro control of 52 and 168 strains of Colletotrichum spp.

Se evaluó la eficiencia in vitro de cinco fungicidas de síntesis química, tres extractos vegetales y tres productos a base de biocontroladores, mediante las variables porcentaje de inhibición del crecimiento micelial y porcentaje de inhibición de la biomasa de Colletotrichum gloeosporioides cepa 52 y Colletotrichum acutatum cepa 168. En el grupo de los productos de síntesis química, los mejores resultados en la inhibición del crecimiento micelial en ambas cepas, se obtuvo con hidróxido de cobre y difenoconazol, con 100% de inhibición. En cuanto a inhibición de la biomasa, los productos con mayor porcentaje de efecto inhibitorio en C. gloeosporioides fueron: difenoconazol (100%) y benomil (93% a 99%); en C. acutatum fueron: difenoconazol (100%) y azoxystrobin (91% a 97%). Respecto a los extractos vegetales, el extracto a base de Citrus sinensis y C. grandis presentó 100% de inhibición tanto del crecimiento micelial como de la biomasa, siendo el más efectivo en el control de ambas cepas del hongo. En el grupo de los biocontroladores, el porcentaje de inhibición del crecimiento micelial de los productos a base de Trichoderma lignorum y T. harzianum osciló entre 61% y 65% para C. gloeosporioides, y entre 77% y 79% para C. acutatum, considerados dentro del grupo de los biocontroladores como los más eficientes en el control in vitro de las cepas 52 y 168 de Colletotrichum spp.