Sensibilidad in vitro de Neopestalotiopsis spp. agente causal de la pudrición de la corona de frutilla a fungicidas de diferentes modos de acción.

Abstract

The objective of this research work was to determine the sensitivity in vitro of Neopestalotiopsis spp. the causal agent of strawberry crown rot to fungicides of different modes of action. Therefore 12 active ingredients were used, according to the classification of the FRAC. The strain of N. mesopotamica used was from the collection maintained by the Phytopathology laboratory at ESPOCH. Calculations were made based on an initial concentration and then sequential dilutions to obtain each of the doses established (0,1; 1; 10; 100; 1000 ppm), with which a solution with PDA medium was created; and fungus disks were transferred; from which diameter measurements were taken every 24 hours. For spore germination, 30 µL of a spore suspension was placed with 30µL of the AI solution on a slide plate, and after 18 hours, the spore count was performed. From which the MCT was obtained: fluazinam (0.01 mm/day), fludioxonil (0.04 mm/day), quintozene (0.05 mm/day), pyraclostrobin (0.04 mm/day) and azoxystrobin (0.09 mm/day). The AIs for mycelial growth control: pyraclostrobin (0.16 mg/L), fluazinam (0.11 mg/L) and fludioxonil (0.26 mg/L), and the AIs with the best results for germination inhibition: fludioxonil (0.1 - 1 mg/L), tebuconazole (0.14 mg/L), fluazinam (0.48 mg/L), thiram (0.57 mg/L). In addition, boscalid was recognized to exhibit insensitivity (˃50 mg/L) by Neopestalotiopsis mesopotamica. While against fludioxonil and pyraclostrobin, it was sensitive (˂1 mg/L). The results obtained are of great importance since the effective dose was not determined by a single method50. They can help future research as a guide to determine the correlation between active ingredients, modes of action, and time of application in the field.