Research Article Identification of Fungal Pathogens of Mango and Soursop Fruits Using Morphological and Molecular Tools and Their Control Using Papaya and Soursop Leaf and Seed Extracts Sara Elena Hern´ andez-Guerrero, 1 Rosendo Balois-Morales , 1,2 Pedro Ulises Bautista-Rosales , 2 Graciela Guadalupe L ´ opez-Guzm´ an, 1 Guillermo Berumen-Varela , 2 Yolotzin Apatzingan Palomino-Hermosillo, 2 Jos´ e Orlando Jimenez-Zurita , 2 Juan Esteban Bello-Lara , 3 and Andr´ es Eloy Le ´ on-Fernandez 3 1 Programa de Doctorado en Ciencias Biol´ ogico Agropecuarias, Universidad Aut´ onoma de Nayarit, Unidad Acad´ emica de Agricultura, Carretera Tepic-Compostela km. 9. C.P. 63780. Xalisco, Tepic, Nayarit, Mexico 2 Unidad de Tecnolog´ ıa de Alimentos, Universidad Aut´ onoma de Nayarit, Avenida de la Cultura S/N Centro, Tepic, Nayarit, Mexico 3 Tecnol´ ogico Nacional de M´ exico, Campus Sur de Nayarit, Carretera crucero Ahuacatl´ an-Jala km. 4.5, C.P. 63880, Jala, Nayarit, Mexico Correspondence should be addressed to Rosendo Balois-Morales; balois_uanayar@hotmail.com Received 30 September 2019; Accepted 21 February 2020; Published 25 March 2020 Academic Editor: Llu´ ıs Palou Copyright © 2020 Sara Elena Hern´ andez-Guerrero et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Fruit and vegetable products are susceptible to the attack of fungi during postharvest handling. Chemical fungicides are the most commonly used technique to control fungal diseases. However, an alternative product is the use of plant extracts, which have been reported in in vitro and in vivo conditions. e objective of this investigation was to identify one of the main pathogens of mango and soursop fruits using morphological and molecular tools as well as to evaluate the in vitro inhibitory effect of papaya and soursop leaf and seed extracts. Two pathogens were isolated and identified by their morphological and molecular characteristics from mango and soursop fruits. We obtained extracts from leaves and seeds of soursop and papaya using five solvents of increasing polarity (hexane, acetone, ethanol, methanol, and water) through the ultrasound-assisted extraction technique at a frequency of 35 kHz and 160 W for 14 min. In vitro evaluations of the extracts were performed using the Kirby–Bauer technique. e extracts with the highest percentage of inhibition were analyzed qualitatively and quantitatively using standardized techniques of colorimetry and spectrophotometry. Furthermore, we determined the content of total phenols, flavonoids, alkaloids, ter- penoids, anthraquinones, coumarins, and saponins. As a result, we identified the pathogens as Colletotrichum fructicola and Nectria haematococca. Aqueous extracts (water as a solvent) showed a higher percentage of inhibition of both pathogens compared with the other extracts. Furthermore, the aqueous extract of papaya leaf was the most effective among all extracts. e aqueous papaya leaf extract exhibited a percentage of inhibition of 49.86% for C. fructicola and 47.89% for N. haematococca. e aqueous extracts of papaya leaf and seed (AqEPL and AqEPS) presented the greatest amount of metabolites (except anthra- quinones and coumarins). e aqueous soursop leaf extract (AqESL) presented the greatest amount of phenols, tannins, and flavonoids (219.14 ± 8.52 mg GAE/L, 159.84 ± 10 mg GAE/g dm and 0.13 ± 1.12 × 10 −4 , respectively). e aqueous soursop seed extract (AqESS) had the highest saponin content with 1.2 ± 0.1mg QSES/g dm and the papaya leaf accusative extract (AqEPL) had the highest alkaloid content (6.413 ± 1 × 10 −3 mg AE/g dm) compared with the other extracts. e AqESS had a lower content of secondary metabolites (sterols, alkaloids, and saponins), while AqESL showed no presence of alkaloids and coumarins. Hindawi International Journal of Agronomy Volume 2020, Article ID 8962328, 15 pages https://doi.org/10.1155/2020/8962328