Los cítricos representan una parte importante de la dieta diaria y son susceptibles de enfermedades de campo y poscosecha causadas por hongos fitopatógenos Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii y Phyllosticta citricarpa. Para su control se emplean fungicida, pero se han observado incrementos en las poblaciones de patógenos capaces de resistir las dosis comerciales. Se aislaron los principales patógenos de cítricos para las pruebas de susceptibilidad posteriores y se los identificó morfológica y molecularmente. Se elaboraron fichas descriptivas de las especies vegetales seleccionadas. Los extractos que resultaron más activos in vitro fueron los de Orthosia virgata, Petiveria alliacea, Funastrum clausum, Albizia inundata, Solanum caavurana, Solanum pilcomayense y Persicaria acuminata. Los aceites esenciales obtenidos de Pelargonium graveolens, Melaleuca linearis y Lippia turbinata demostraron un buen desempeño frente a dos de los patógenos estudiados (P. digitatum y P. italicum). En los ensayos de poscosecha con naranjas var. ´Salustiana´, los extractos diclorometánico de S. pilcomayense y de P. acuminata redujeron considerablemente la incidencia y severidad de la enfermedad causada por P. digitatum; el extracto diclorometánico de S. pilcomayense y el aceite esencial de L. turbinata fueron capaces de controlar a P. italicum; mientras que el extracto diclorometánico de P. acuminata redujo la severidad de la enfermedad causada por G. citri-aurantii. Mediante la técnica CG-EM se halló la presencia de D-limoneno, 1,8-cineol, isómeros de terpineol y geraniol como principales componentes. Se concluye que los productos naturales evaluados, controlan algunos patógenos de cítricos in vitro y en la etapa de poscosecha.
Citrus fruits represent an important part of the daily diet and are susceptible to field and postharvest diseases caused by phytopathogenic fungi such as Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, and Phyllosticta citricarpa. Fungicides are used for their control; however, increases in pathogen populations capable of resisting commercial doses have been observed. The main citrus pathogens were isolated for subsequent susceptibility testing and were identified both morphologically and molecularly. Descriptive records of the selected plant species were prepared. The most active extracts in vitro were those of Orthosia virgata, Petiveria alliacea, Funastrum clausum, Albizia inundata, Solanum caavurana, Solanum pilcomayense, and Persicaria acuminata. Essential oils obtained from Pelargonium graveolens, Melaleuca linearis, and Lippia turbinata showed good performance against two of the studied pathogens (P. digitatum and P. italicum). In postharvest trials with 'Salustiana' oranges, the dichloromethane extracts of S. pilcomayense and P. acuminata significantly reduced the incidence and severity of the disease caused by P. digitatum; the dichloromethane extract of S. pilcomayense and the essential oil of L. turbinata were able to control P. italicum; while the dichloromethane extract of P. acuminata reduced the severity of the disease caused by G. citri-aurantii. the phytochemical profile of the obtained essential oils was analyzed using gas chromatography-mass spectrometry (GC-MS), revealing that the most active oils contained D-limonene, 1,8-cineole, terpineol isomers, and geraniol as their main components. The natural products evaluated in this thesis effectively control certain citrus pathogens both in vitro and during the postharvest stage.
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