Revista de la Facultad de Agronomía de la Universidad del Zulia

Biocontrol of Cosmopolites sordidus using entomopathogenic fungi under laboratory conditions, Ecuador

2025-04-21T21:30:50+00:00

Cosmopolites sordidus known as the black weevil, is an insect pest of economic importance for Musaceae crops such as bananas and plantain, resulting in production losses due to its damage. One of the alternatives for the management of the black weevil is biological control using entomopathogens that regulate the insect populations in Musaceae plantations. The objective of the research was to determine the action of the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, and Verticillium lecanii on adults of the black banana weevil under controlled laboratory conditions. A completely randomized design was implemented with 8 treatments with the application of the entomopathogens individually and in combinations, as well as a control treatment. The results showed that the treatment with the combination of B. bassiana + M. anisopliae showed the best control of the insect pest with 100 % mortality 10 days after inoculation, followed by B. bassiana with 88 % and 24% control with M. anisopliae, while the treatment with the fungus V. lecanii achieved 32 % control of the black weevil. Entomopathogens are an alternative for the management of the insect pest of Musaceae C. sordidus.

Morphological and genetic variability of chili pepper (Capsicum annuum L.) populations from northern of Mexico

2025-04-14T18:02:16+00:00

This study investigated the genetic and morphological variability of five domesticated chili varieties (Árbol, Güerito, Mirasol, Negro and Alcalá) and one wild variety (chiltepín) from Chihuahua, Mexico. Morphological evaluation was carried out according to the International Plant Genetic Resources Institute, combining correspondence analyses and Chi-square tests. Genetic variability was determined using the RAPD technique; a dendrogram was constructed, and genetic diversity among populations was estimated using principal coordinate methods, Shannon index, and permutational multivariate analysis. The morphological analysis revealed significant variations, while the genetic analysis, using the RAPD technique, showed 79.5 % polymorphism, indicating considerable diversity among the varieties. The dendrogram revealed the presence of three groups, highlighting chiltepín as potential ancestor of the domesticated varieties. The study emphasizes the importance of conserving and improving these plant genetic resources.

Multivariate analysis in the characterization of feijoa fruits (Acca sellowiana [O. Berg] Burret) in Tungurahua, Ecuador

2025-04-14T19:26:06+00:00

The feijoa (Acca sellowiana [O. Berg] Burret) is a Myrtaceae native to southern Brazil and northern Uruguay. Its fruits can be consumed fresh or processed into juice, ice cream, wine, liqueurs and others. In Ecuador, feijoa cultivation has been reported since 1980 in the province of Tungurahua. To evaluate the morphological and physicochemical characteristics of feijoa fruits through multivariate analysis, fruits from 18 farms located in Tungurahua, Ecuador were analyzed. A sample of 10 fruits per farm were analyzed in the food processing laboratory of the Tungurahua Higher Technological Institute. Descriptive statistics and multivariate analysis were employed for data evaluation. The fruits exhibited an oboval shape with erect sepals, moderate skin roughness, and white pulp. Fruit diameter ranged from 2.0 to 5.1 cm (CV=17 %), and fruit length ranged from 2.46 to 10.1 cm (CV=16.2 %), indicating variability in fruit size. Fruit biomass ranged from 8 to 133 g, with pulp yields between 4.6 % and 46.2 %. Total soluble solids ranged from 8.0 to 20 °Brix; the pH and titratable acidity (citric acid percentege) averaged 3.5 and 0.50, respectively. Fruit length and diameter showed a high correlation with fruit biomass. PCA identified the formation of three groups of producers, based on fruit size

Effect of organic and inorganic fertilization on the growth and yield of Gossypium hirsutum L. in Ecuador

2025-04-19T18:30:36+00:00

The cultivation of cotton (Gossypium hirsutum L.) has a significant impact on the global economic and agricultural sectors, with its productivity being closely linked to nutrient management and the sustainability of the production system. The objective of this study was to evaluate the effect of organic and inorganic fertilization on the growth and yield of G. hirsutum in Ecuador. A completely randomized block design was used with a 2×4×2 factorial arrangement, which included two nitrogen sources (organic matter and urea), four nitrogen fertilization rates (50, 100, 150, and 200 kg N.ha^-1), and the presence or absence of efficient microorganisms (EM). Phenological, morphometric, and yield-related variables were measured, along with foliar concentrations of N, P, and K. The results indicated that urea fertilization promoted greater vegetative growth and yield, while organic matter enhanced foliar potassium uptake. The application of efficient microorganisms (EM) did not produce statistically significant differences compared to the control treatment across all evaluated variables, as it significantly increased yield. Moreover, the interaction between nitrogen sources and fertilization rates showed that the combination of 150 kg N.ha^-1 with EM optimized production. Inorganic fertilization with urea maximized cotton productivity, while organic matter contributed to a more sustainable production system, promoting sustainable agriculture.

Effect of herbicides on the growth of beneficial microorganisms in rhizospheric soil

2025-05-01T20:27:57+00:00

This research seeks to understand the impact of herbicides on beneficial soil microorganisms, essential for agricultural health, and contribute to more sustainable management practices. The study aimed to evaluate the effect of herbicides commonly used in conventional agriculture, such as glyphosate, paraquat, and MCPA, on the growth of beneficial soil microorganisms. The microorganisms were isolated from the rhizosphere soil of a CCN-51 cacao crop from a production farm in Ecuador, and identified through morphological characterization and molecular analysis. The detected beneficial microorganisms were seeded in culture media with field-used doses of the different herbicides mentioned above, and mycelial growth in fungi (Trichoderma asperellum) and colony extension in bacteria (Bacillus subtilis and Pseudomonas fluorescens) were evaluated. The results showed that the herbicides had a significant inhibitory effect on the growth of these beneficial microorganisms. In the case of T. asperellum, paraquat and MCPA showed greater mycelial inhibition compared to glyphosate. Furthermore, all three herbicides significantly reduced the growth of B. subtilis and P. fluorescens, in contrast to the control groups, which maintained constant growth. These findings suggest that the herbicides studied may have a negative impact on the growth dynamics of beneficial microorganisms, which could affect the balance of the agricultural ecosystem. These results highlight the importance of considering the potential effects of herbicides on the soil microbiota in the management of sustainable agricultural systems.

Correlation between UAV multispectral Imagery and spectroradiometer measurements in sunflower developmental stages

2025-05-02T14:55:37+00:00

Oilseed crops are among the product groups with a supply deficit in the world. The sunflower oil crisis experienced after 2020 ha increased the importance of sunflower cultivation. The most important stages in agricultural applications are to understand whether the plant is healthy in the early stages before it is formed and to prevent negative results in harvest. With the developing technology, the use of unmanned aerial vehicles (UAVs) and multispectral cameras in agricultural applications has gained enormous importance. Thanks to UAVs, agricultural temporal resolution can be adjusted according to the user's request, and spatial resolution can be adjusted according to the ability of the sensor used and the flight altitude. Spectral resolution is directly proportional to the number of bands and the band wavelength. We performed correlation analysis in this study by comparing the accuracy of the band values with ground measurements made with a spectroradiometer. We measured the sunflower in its vegetative, R-3, and R-5 phases and found that there was a strong correlation (r=0.894) in the green band, r=0.845 in the red, r=0.789 in the red edge (RE) band, and r=0.725 in the near infrared band (NIR). The results show a strong connection between the spectral bands and the spectroradiometer measurements, especially in the green and red bands.

A systematic review of COVID-19 effects on agri-food chains in Latin America

2025-05-01T19:21:22+00:00

The rise of the COVID-19 pandemic generated large effects on global supply chains. These effects are especially relevant in agriculture, as they compromised food security. The present study is a systematic review of peer-reviewed scientific literature to understand the effects of the pandemic on agro-food chains and links in Latin America. The documented effects are mainly negative (81.5 %) and translated into impacts on production systems (32.3 %) and markets (24.6 %). It was reported that the impacts on production were due to difficulties in labor mobility, interruption of the supply chain, closure of external markets and increased transportation costs. Transportation was the link with the most difficulties due to restrictions on mobilization, even though it was the least referenced. There were negative impacts on processing, due to the shortage of raw materials and the interruption or closure of industries. On the other hand, some positive effects were reported, such as the development of local markets, the emergence of alternative products and digital markets with direct home delivery, as well as a shift towards healthy consumer habits. Agricultural policy makers should take these results into account when proposing strategies to develop more resilient agrifood chains to face challenges such as those caused by the Covid-19 pandemic.