Examinando por Autor "Leiva Espinoza, Santos Triunfo"

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Identification of Metamasius hemipterus (Coleoptera: Dryophthoridae) and its biological control through the use of species of the genus Beauveria and Metarhizium. Amazonas, Peru
(Frontiers Media S.A, 2026-01-12) Leiva Espinoza, Santos Triunfo; Román Peña, Alcides; Aguilar, Vilma; Requejo, Elizabeth; Meza Maicelo, Wagner; Banda Martinez, Duber; Huaman Pilco, Ángel Fernando; Loyola , Fredy; Loja, Melissa; Oliva Cruz, Manuel; Maicelo Quintana, Jorge
Biological control of insect pests represents a key strategy toward sustainable agriculture. This study, focused on the morphological and molecular identification of the sugarcane weevil, Metamasius hemipterus, (Coleoptera: Dryophthoridae), and on the evaluation of the biocontrol potential of four entomopathogenic fungi: Beauveria bassiana, Metarhizium anisopliae, Beauveria peruviensis, and Metarhizium sp. Molecular identification was conducted through phylogenetic analysis, while morphological identification was based on the description of characteristics following established protocols. Both approaches confirmed the identity of the pest as Metamasius hemipterus L. Bioassays were carried out under a completely randomized design, testing four conidial concentrations, plus a control. Metarhizium anisopliae at 1 × 10¹⁰ conidia/mL was the most virulent, producing the highest mortality and exhibiting the lowest lethal concentration (LC₅₀ = 2.68 × 10⁹ conidia/mL) against Metamasius hemipterus adults. Conversely, Beauveria peruviensis at 1 × 10¹⁴ conidia/mL achieved the highest colonization efficiency in insect cadavers, with a mycosis rate of 99.4%. These findings indicate that Beauveria peruviensis and Metarhizium anisopliae are promising biological control agents against the sugarcane weevil, the major pest of sugarcane in the Amazonas region of Peru.
Synergistic effects of potassium and gibberellin on the yield and quality of yellow pitahaya (Hylocereus megalanthus) fruits in the Peruvian Amazon
(Frontiers Media S.A., 2025-11-24) Santos Pelaez, Julio Cesar; Leiva Espinoza, Santos Triunfo; Espinoza Núñez, Erick; Saravia Navarro, David; Castillo Torrejon, Carlos Luis; Cruz Delgado, Julio Humberto Ignacio; Klauer Garcia, Dieter Fritz; Casanova Nuñez Melgar, David Pavel
The cultivation of yellow pitahaya (Hylocereus megalanthus) is increasing in tropical regions due to its nutritional value and market potential. Yet, agronomic strategies integrating nutrient and hormonal regulation remain scarcely studied. This research evaluated the combined effect of potassium (K₂O) and gibberellic acid (GA₃) on yield and fruit quality in field-grown pitahaya in the Peruvian Amazon using a 4 × 2 factorial randomized block design with four potassium doses (0, 50, 100, 150 kg ha⁻¹) and two GA₃ levels (0 and 50 mg L⁻¹). The combination of 100 kg K₂O ha⁻¹ and 50 mg L⁻¹ GA₃ significantly improved fruit performance, with fruit weight (369.5 g), yield (12 t ha⁻¹), volume (322 cm³), and soluble solids (22.8°Brix), while acidity decreased (pH 4.87 vs. 4.55 in the control). Potassium alone had a limited impact on fruit weight per plant, but under GA₃ application, a quadratic response was evident, with maximum values between 100–110 kg K ha⁻¹. Multivariate analyses confirmed that yield gains were driven by increases in fruit size and quality, with fertilized treatments clearly separated from controls. These findings demonstrate a synergistic interaction between potassium and GA₃, providing a basis for precision fertilization protocols that enhance yield and quality in high-value tropical fruit systems.