Revista de la Facultad de Agronomía de la Universidad del Zulia

The unwavering resilience of scientific research in Latin America

2025-12-28T23:40:04+00:00

Science in Latin America develops in an environment marked by constant adversity, and empirical research in our region is a living testimony to human strength. From laboratories with infrastructural limitations in South American public institutions to the most advanced innovation centres in Central America, academics have demonstrated an extraordinary ability to forge ahead despite fiscal constraints, brain drain and socio-economic ups and downs. This tenacity goes beyond mere survival: it is a collective effort that redefines what seems possible.

Capsaicin in the control of Spodoptera frugiperda in corn (Zea mays L.) var. Blanco Urubamba

2025-12-26T21:19:00+00:00

Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) causes severe losses in corn (Zea mays L.) crops, which leads to the evaluation of sustainable management alternatives. The objective of this research was to determine the efficacy of capsaicin in controlling S. frugiperda in the corn Blanco Urubamba var. A randomized complete block design with six treatments and three replicates was used: four concentrations of water-soluble capsaicin (6.70; 10.05; 13.40 and 16.75 mL.L^-¹), rocoto pepper extract (Capsicum pubescens Ruiz & Pav. (Solanaceae), 50 g.L^-¹), and an absolute control. Applications were made at 80, 90, 100, 110, and 120 days after sowing (das). The 16.75 mL.L^-¹ dose was the most effective, reducing larval density from 3.12 to 0.13 larvae per plant, and the infestation percentage from 61.12 to 2.78 %, with a control efficacy of 96.69%. Intermediate concentrations (13.40 and 10.05 mL.L^-1) also showed significant effects, with final efficacies of 93.83 and 85.19 %, respectively. T1 had moderate efficacy (78.30%), while T5 recorded the lowest control values (72.86 %), with increasing infestations being observed in the control. In terms of yield, T4 (16.75 mL.L^-¹) produced ears of 16.77 cm in length and 385.13 g in average weight, reaching a yield of 17.12 t.ha^-¹ compared to 9.54 t.ha^-¹ for the control. In conclusion, water-soluble capsaicin, especially at 16.75 mL.L^-¹, proved to be an effective and sustainable alternative for the management of S. frugiperda in corn.

Effectiveness of sex pheromone traps in the integrated management of Planococcus ficus Signoret (Hemiptera: Pseudococcidae) in vineyards

2025-12-28T23:12:58+00:00

Planococcus ficus (Signoret) represents an economically significant pest in viticulture, requiring timely, innovative, and effective control measures. While the application of sex pheromones in vineyards has primarily focused on mating disruption, there is a lack of studies evaluating their use in mass trapping as a management tool for this pest. This study was conducted in a commercial vineyard of the Crimson Seedless variety in Ica, Peru, and the objective was the efficacy of pheromone-baited traps (CINNAFIC®) deployed from postharvest 2020 through postharvest 2021. During this period, a trap density of 15 traps.ha⁻¹ was maintained, resulting in the capture of 16,927 males, with a peak capture rate of 112.20 males.trap⁻¹.week⁻¹ observed during the berry development stage. The greatest control was observed at harvest, with a 59.12 % reduction in the total mealybug population, highlighted by the production of infestation-free, fully exportable grape clusters, compared to 7 % infestation in control plots. Trap deployment limited mating opportunities, significantly altering the population structure by reducing nymphs and ovipositing females in treated plots. These results demonstrate that integrating pheromone traps with cultural practices and timely applications of pesticides and botanical extracts enables effective mealybug control without exclusive reliance on chemical insecticides. It is concluded that pheromone traps constitute a sustainable, effective, and viable tool for the integrated management of P. ficus in vineyards.

Entomopathogenic potential of thermotolerant microorganisms isolated from infected Dermestes maculatus against Culex pipiens larvae

2025-12-28T23:32:47+00:00

During summer, when temperatures reach extreme records, the inhabitants Sahara seek refuge in oases for shade and water. These ecosystems are characterized by a unique microclimate. Nevertheless, they face serious threats from two arthropod species: venomous scorpions and mosquitoes, which act as vectors of diseases. Chemicals impacting both biotic and abiotic components of the ecosystem, and more critically human health. Chitinolytic entomopathogenic microorganisms were isolated from dust samples collected from the cadavers of the Dermestes maculatus. Chitin extracted from shrimp shells (yield: 16.6 %) served as the sole carbon source in the selective culture media employed for their cultivation. Five strains were obtained: three fungi (Aspergillus flavus, A. fumigatus, Mucor sp.) and two bacteria (Bacillus sp. and Actinomycete). Bioassays against third-instar Culex pipiens larvae showed that Actinomycete (10⁶ CFU.mL^-1) induced 90 % of mortality, followed by A. fumigatus, Mucor sp., and Bacillus sp. (80 %), Data were analyzed using one-way ANOVA and Duncan’s test (p<0.05). Microscopic observations revealed severe larval deformities. These findings confirm the strong larvicidal potential of microorganisms as eco-friendly alternatives to chemical insecticides.

Hydrodynamic and hydrochemical levels of groundwater in perennial crops of the Vinces canton, Los Ríos, Ecuador

2026-01-18T17:52:49+00:00

The static and dynamic levels, as well as the quality of groundwater sources used for agricultural production, represent an important factor in understanding the characteristics of the use of wells for this activity and the influence on the decline in static levels during the dry season. The objective of this research was to determine the behavior of the hydrodynamic and hydrochemical levels of groundwater used in plantain, banana, and cocoa production to improve water resource utilization in the Clariza parish of the Vinces canton, Ecuador. Data were collected from 10 production units in the area. For the dynamic levels, a constant-rate pumping test was performed. For water quality characteristics, in-situ tests for pH, electrical conductivity (EC), and total dissolved solids (TDS) were performed, and no values were recorded that would restrict their use for agricultural activities. The declines in dynamic levels were constant and progressive during the dry season due to the irrational use of water through pumping systems. Dynamic levels measured using the pumping test determined maximum drawdowns between 6 and 8 m in depth; however, well recovery showed constant rising levels, indicating aquifer recharge.

Rhizospheric plant growth-promoting bacteria (PGPR) in corn plants

2026-01-28T22:37:19+00:00

PGPR are considered a sustainable alternative to improve crop productivity, for its ability to biostimulate plant growth, induce systemic resistance, increasing tolerance to abiotic stress, among other benefits. The objective of the study was to evaluate the effect of plant growth-promoting rhizosphere bacteria (PGPR) on the germination and development of corn plants. Seven strains obtained from the Biotechnology Research Center (CEB) of the Santa Elena Peninsula State University, Ecuador, were reactivated, corn seeds were inoculated, and planted to evaluate germination and plant development in two stages (laboratory and nursery). The rhizobacteria significantly promoted germination by up to 17 %, emergence, and initial growth of corn, especially the species Stenotrophomonas pavanii and Pantoea dispersa. In addition, P. dispersa (b) species increased stomatal density on both leaf surfaces, which could be associated with better photosynthetic efficiency and water use. In conclusion, S. pavanii and P. dispersa strains promote germination and growth of Azor corn, the phylogenetic analysis indicates close groupings with reference isolates for their efficacy with significant potential such as (PGPR) with documented biotechnological capabilities for the genera Pantoea and Stenotrophomonas.

Exogenous applied proline may enhance the tolerance of sweet sorghum (Sorghum bicolor (L.) Moench) under water deficit stress

2026-01-29T01:47:28+00:00

Drought is a major abiotic stress that threatens global food security by reducing crop yield and quality. Foliar application of osmoprotectants such as proline offers a promising means to mitigate drought-induced damage. This study examined the effects of exogenous proline (P0, P200, P400, and P600 mg.L^-1), sorghum genotype, and their interaction on morphological, physiological, biochemical, forage quality, and microbial traits under different drought levels (I100, I75, I50, and I25). Proline application increased dry matter by over 100 % under medium to severe deficits and enhanced root dry weight by 90 % at 75 % water reduction. The strongest response occurred in chlorophyll content (SPAD), reflecting improved photosynthetic stability. Exogenous proline reduced leaf drying by 25 % and alleviated drought-related declines in forage quality, as evidenced by improvements in NDF, ADF, and ADL. It also boosted peroxidase activity more than superoxide dismutase and catalase, minimizing hydrogen peroxide (H₂O₂) toxicity and oxidative stress. Even under extreme drought (I25), proline maintained plant vigor and improved water-use efficiency by 25 - 40 % at the seedling stage. Compared with the control, leaf chlorophyll content (SPAD values) decreased by 13.91 %, 24.28 %, and 31.85 % under the I75, I50, and I25 treatments, respectively, suggesting that SPAD measurements at the seedling stage may serve as a practical and cost-effective indicator for identifying drought-tolerant sorghum genotypes.

Age-related variation and multivariate analysis of internal and external egg quality traits in ISA Brown hens

2025-12-28T23:06:26+00:00

This study evaluated age-related variations in internal and external egg quality traits in ISA Brown hens raised under semi-arid Algerian conditions. Hens were assessed at two production stages: 5,977 at peak lay (25–30 weeks) and 5,430 at late lay (75–80 weeks). A total of 360 eggs were collected (180 per stage), at a rate of 30 eggs per week, randomly selected at the beginning of each week. Egg weight, shell thickness, shape index, yolk and albumen indices, Haugh units, and yolk color were measured. A one-way analysis of variance (ANOVA) was used to detect age-related differences, Pearson correlation to examine interrelationships among traits, and principal component analysis (PCA) to identify general age-related patterns. Significant differences were observed between the two laying stages. Peak-lay eggs showed superior internal quality, particularly in albumen height and Haugh units, whereas late-lay eggs exhibited greater mass but reduced albumen integrity. Shell thickness and yolk shape remained relatively stable. Correlation analysis revealed stronger trait associations during peak lay, which weakened with advancing age. PCA showed contrasting age-related trends between egg size and internal quality: egg size increased with age, whereas internal quality declined, while shell- and yolk-related traits remained relatively constant. The findings of this study apply to hens up to 80 weeks of age. Further studies covering longer production cycles are recommended to determine whether these patterns persist beyond this period.

Chemical composition of Urochloa and Megathyrsus maximus cultivars under tropical humid forest conditions

2026-01-11T17:06:37+00:00

Urochloa and Megathyrsus maximus comprise the most widely sown grasses in Venezuela, and their composition is influenced by management practices and the rainfall regime in the region. The chemical composition of seven grass cultivars (CV) was evaluated
during the dry and rainy seasons (SE) under two (4 and 6 weeks) defoliation frequencies (DF) in tropical humid forest conditions
of the Catatumbo municipality, Zulia state, Venezuela. Dry Matter DM), Ash (ASH), Ether Extract (EE), Crude Protein (CP) and
Crude Fiber (CF) were measured. A randomized complete block design with a split-plot arrangement and four replications per
cultivar was used. Highly significant effects (p<0.01) of SE were observed on ASH, EE and CF contents. Defoliation frequency
significantly affected (p<0.01) all evaluated variables, with notable CP contents in cultivars BR02/0465 (10.36 %) and CIAT 606
(10.17 %). Considering SE, CV and DF together, highly significant effects (p<0.01) were determined on EE contents of M. maximus cv.
Tanzania (2.59 %) and CIAT BR02/0465 (2.39 %) during the dry SE at DF 4 weeks. Regarding CF, significant decreases (p<0.01) were
recorded as the age advanced from 4 to 6 weeks in cultivars Tanzania (26.87 % to 26.66 %), BR02/0465 (25.03 % to 21.68 %) and Mulato
II (24.81 % to 20.46 %). From a bromatological perspective, the evaluated cultivars demonstrated high nutritional value, particularly
CIAT BR02/0465, identifying it as a promising option for the tropical humid forest of El Guayabo.

Laying rate and egg quality of three hen genotypes in family farming of southwest Algeria

2026-01-29T00:56:36+00:00

The quality and number of eggs produced by laying hens introduced into family oasis farms in southwestern Algeria remain poorly studied. This study evaluated the effect of genotype (local hen, Fayoumi, and Plymouth Rock) on egg quality. A total of 180 eggs (60 per genotype) were collected over one year, and their external characteristics (egg weight, length, width, shape index and shell weight) and internal characteristics (yolk weight and albumen weight) were analyzed. A one-way analysis of variance (ANOVA) was used to assess the effect of genotype on the measured egg characteristics. Post hoc comparisons were conducted using Tukey's HSD test. The results showed that genotype had a significant effect on several traits. Egg weight (P<0.05), length (P<0.05), width (P<0.001), shell weight (P<0.001) and albumen weight (P<0.05) differed among genotypes. The shape index also varied (P<0.001), reflecting distinct egg morphology. The external measures were egg weight (Local hen: 44.42 g, Fayoumi: 40.07 g, Plymouth: 46.79 g), length (Local hen: 52.06 mm, Fayoumi: 46.58 mm, Plymouth: 48.80 mm), and width (Local hen: 36.93 mm, Fayoumi: 34.20 mm, Plymouth: 36.58 mm). The internal measures were yolk weight (Local hen: 15.00 g, Fayoumi: 14.37 g, Plymouth: 14.93 g) and albumen weight (Local hen: 24.72 g, Fayoumi: 23.40 g, Plymouth: 27.28 g). In conclusion, the study highlights the importance of considering genetic factors in poultry selection and improvement programs, particularly in family farming systems in southwest Algeria, where improving productivity and egg quality is essential for food security and improving farmers’ livelihoods.

Elaboration of “cacho de cabra” chilli canned (Capsicum annum L. Var Longum) in three different coverage media

2025-12-26T21:52:48+00:00

The "cacho de cabra" chili pepper (Capsicum annuum L.) is used in the preparation of a wide variety of foods, primarily consumed in dehydrated, raw, or powdered form to flavor and aromatize dishes. To contribute to the development of different types of products using the "cacho de cabra" chili pepper (Capsicum annuum L. var. Longum) as a raw material, a canned version of this chili pepper was developed, considering the covering medium, the amount of NaCl, citric acid, and spices. Three treatments were proposed for this process. The chemical characteristics, sensory attributes, and safety of the manufactured products were evaluated. Analyses of chemical characteristics (sodium content, total acidity, and pH), sensory attributes (color, flavor, aroma, texture, and overall acceptability), and safety (fecal and total coliforms) were performed after 20 and 40 days of storage. Canned goods prepared with treatment T₀ (water + 2 % NaCl + citric acid) were the most accepted by the panelists, followed by those prepared with treatment T₁ (sunflower oil + spices). Canned goods prepared with treatment T₂ (extra virgin olive oil) were not well-received due to their acidic taste and mealy texture. Significant results were found in all three treatments for sodium content, pH, total acidity, and absence of pathogenic microorganisms.

Antioxidant and antimicrobial activities of sustainable Salvia hispanica L. seed extracts against gram-positive and gram-negative bacteria

2026-01-18T18:49:16+00:00

Salvia hispanica L. (chia) seeds are rich in bioactive compounds with antioxidant and antimicrobial properties, making them valuable natural ingredients for food and agro-industrial applications. Food contamination by Gram-positive and Gram-negative bacteria remains a major challenge for food safety, highlighting the need for sustainable natural preservatives. This study aimed to compare two green extraction methods for recovering bioactive compounds from Algerian dark chia seeds and to evaluate the antioxidant and antimicrobial activities of the resulting extracts against Gram-positive and Gram-negative bacteria. Aqueous Soxhlet extraction and ethanolic maceration were applied. Extracts were analyzed for total phenolics and flavonoids, antioxidant activity (DPPH assay), and antimicrobial activity using the disc diffusion method against nine microbial strains, including Gram-positive and Gram-negative bacteria and Candida albicans. The aqueous Soxhlet extract exhibited the highest total phenolic content and strong antioxidant activity (88 % DPPH inhibition at 400 μg.mL^-¹). The ethanolic maceration extract was richer in flavonoids and showed moderate, dose-dependent antimicrobial activity. Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) were most sensitive (up to 12 ± 1 mm), while Gram-negative bacteria were generally more resistant, except Klebsiella pneumoniae (15 ± 1 mm at 15 mg.mL^-¹). Candida albicans was highly susceptible (14 ± 1 mm). Green-extracted chia seed extracts demonstrate significant antioxidant and moderate antimicrobial activities, supporting their potential use in food preservation, sustainable product development, and eco-friendly agro-industrial applications.