Natalia Escobar Escobar

The in vitro anthelmintic effect of the extracts on Haemonchus contortus (H. contortus) of three forage species in the tropical dry forest is known; however, there is no information about the effects of the extract partitions, nor their chemical composition. The objectives of this study were to evaluate the in vitro ovicidal activity of H. contortus in extract partitions of the species Gliricidia sepium, Leucaena leucocephala, and Pithecellobium dulce, and to identify the compounds present in the extract partitions with the highest activity by employing ultra HPLC Quadrupole orbitrap mass spectrometry. Four extract partitions, hexane, dichloromethane, ethyl acetate, and hydroethanolic from the three forage species were assessed in an inhibition of egg hatching (IEH) assay. The extract partitions with the highest anthelmintic activity (AA) were subjected to analysis, from which the tentative identification of the compounds was established. The extract partitions, including dichloromethane from Gliricidia sepium, ethyl acetate from Leucaena leucocephala, and hydroethanolic from Pithecellobium dulce showed a greater anthelmintic effect, with IC₅₀ values of 0.39, 0.86, and 0.27 mg/mL for the IEH, respectively. Metabolites with in vitro AA potential included flavonoids, fatty acid esters, hydroxycinnamic acids, organic oxygenated compounds of the benzene class and substituted derivatives, phenolic glycosides, and phenols.

Objective: Knowing and studying insects associated to an agroecosystem allow us to establish functional groups that enable the populations’ self-regulation and promote the provision of ecosystem services. Scope: In order to assess the presence of functional groups of insects associated to family farming and agroecological practices in the province of Sumapaz, Cundinamarca (Colombia), a pilot test was designed. Methodology: Sampling was performed on 11 family farms in the municipalities of Arbelaez, Fusagasuga, Granada and Tibacuy. The farms were also classified into 3 different groups: group 1 (organic producers), group 2 (producers in organic conversion process), group 3 (conventional producers). Two samples were taken on each farm between March and June-2017, using pitfall traps and capture of flying insects with an entomological net. Main Results: One thousand six hundred fifty-one specimens were collected and classified in 11 orders, 60 families and 179 morphospecies, 976 of them were beneficial insects (predators, decomposers, parasitoids and pollinators) and 675 insects were considered pests (defoliating phytophagous, sucking phytophagous and generalist phytophagous). Group 1 reported the highest number (425) of beneficial insects, while group 3 had the highest number (356) of pest insects. The most representative family in the three groups was Formicidae, with 421 specimens. In addition, the finding of genus Mordellistena (Coleoptera: Mordellidae: Mordellistenini) was registered for the first time for the department of Cundinamarca. Conclusions: From this information, the establishment of functional groups indicates the state of these agroecosystems, where the organic farms guarantee a better pollination and pest control, unlike the conventional ones.

In the present work, the anthelmintic activity (AA) of ethanolic extracts obtained from Gliricidia sepium, Leucaena leucocephala, and Pithecellobium dulce was evaluated using the third-stage-larval (L₃) exsheathment inhibition test (LEIT) and egg hatch test (EHT) on Haemonchus contortus. Extracts were tested at concentrations of 0.3, 0.6, 1.2, 2.5, 5.0, 10, 20, and 40 mg/mL. The larval exsheathment inhibition (LEI) results showed that G. sepium achieved the highest average inhibition of 91.2%, compared with 44.6% for P. dulce and 41.0% for L. leucocephala at a concentration of 40 mg/mL; the corresponding IC₅₀ values were 22.4, 41.7, and 43.3 mg/mL, respectively. The rates of egg hatching inhibition (EHI) at a concentration of 5 mg/mL were 99.5% for G. sepium, 64.2% for P. dulce, and 54% for L. leucocephala; the corresponding IC₅₀ values were 1.9 mg/mL for G. sepium, 3.9 mg/mL for P. dulce, and 4.3 mg/mL for L. leucocephala. The species extracts studied here were also analyzed by ultra-high performance liquid chromatography and Orbitrap high resolution mass spectrometry (UHPLC-Q/Orbitrap/MS/MS), resulting in the compounds’ identification associated with AA. Glycosylated flavonoids and methoxyphenols were observed in all three species: fatty acids in G. sepium and P. dulce; phenylpropanoids, anthraquinone glycosides, amino acids and glycosylated phenolic acids in G. sepium; and flavonoids in L. leucocephala. Comparatively, G. sepium presented a greater diversity of compounds potentially active against the control of gastrointestinal nematodes, which was associated with the results obtained in the applied tests.

Maize is currently the world’s second largest crop in terms of production, after wheat and rice. It is the first cereal as for grain yield per hectare and the second, after wheat, regarding total production. Maize has great economic importance worldwide, both as human and/or animal food, and as a source of a large number of industrial products. New digital technologies are allowing greater monitoring of farming production stages. This research developed the spectral signature of maize fields ground covers across different growth stages (2 months, 2.3 months and 4.3 months). Similarly, this research paper proposes the application of a methodology based on four phases: 1. Maize crop georeferencing, 2. Satellite images selection, 3. Radiometric calibration of images 4. Spectral signature development of maize crops. Spectral response or signature of maize crops at visible and near-infrared wavelengths was obtained, indicating significant changes in crops growth. The use of satellite imagery becomes an interesting tool that introduces an approach towards more accurate and controlled monitoring systems in agricultural production.