Tesis
Sensibilidad in vitro de Neoscytalidium spp. agente causal del cáncer de la pitahaya a fungicidas de diferentes modos de acción.
Fecha
2022-05-11Registro en:
Yumbo Grefa, Yalic. (2022). Sensibilidad in vitro de Neoscytalidium spp. agente causal del cáncer de la pitahaya a fungicidas de diferentes modos de acción. Escuela Superior Politécnica de Chimborazo. Riobamba.
Autor
Yumbo Grefa, Yalic
Resumen
The objective of this research was to determine the in vitro sensitivity of Neoscytalidium spp. the
causal agent of pitahaya cancer to fungicides of different modes of action. Therefore 12 active
ingredients were used, according to the classification of the Fungicide Resistance Action
Committee (FRAC). There were three active ingredients from the respiration group, two from
membrane sterol biosynthesis, two from motor and cytoskeleton proteins, one from amino acid
and protein synthesis, one from chemicals with multi-site activity, one from plant host defense
induction, one from lipid transport or synthesis/membrane function or integrity, and one from
unclassified. Nine strains isolated from pitahaya cultivars from the Guayas and Los Ríos
provinces were used. Calculations were made based on an initial concentration from which
sequential dilutions were carried out to obtain each of the doses established in the research (0; 0.1;
1; 10; 100; 500 ppm), with which a solution with PDA medium was created and Neoscytalidium
spp. discs were transferred, from which diameter measurements were taken every 24 hours. The
results obtained were tabulated in Excel and then entered the RStudio program for the
descriptive statistical analysis of the Effective Dose 50 (DE50) showing strains with sensitive
ranges in the products methyl thiophanate with 7 strains (87, 5%), tebuconazole with 5 strains
(55.55%), thiabendazole, difenoconazole, and azoxystrobin with 3 strains each (33.33%) and
pyraclostrobin with 2 strains (22.22%). It was concluded that at DE50, boscalid and copper sulfate
showed resistance at all the doses studied. It is recommended that other active ingredients with
the same mode of action used in this study be tested to determine whether cross-resistance
exists.