Revista de Ciencias Agrícolas

Use of Trained Convolutional Neural Networks for Analysis of Symptoms Caused by Botrytis fabae Sard

David-E Álvarez-Sánchez — 2023-04-24

This study evaluated the use of convolutional neural networks (CNN) in agricultural disease recognition, specifically for Botrytis fabae symptoms. An experimental bean culture was used to capture images of healthy and affected leaflets, which were then used to perform binary classification and severity classification tests using several CNN models. The results showed that CNN models achieved high accuracy in binary classification, but performance decreased in severity classification due to the complexity of the task. InceptionResNet and ResNet101 were the models that performed best in this task. The study also utilized the Grad-CAM algorithm to identify the most significant B. fabae symptoms recognized by the CNNs. Overall, these findings can be used to develop a smart farming tool for crop production support and plant pathology research.

Response of commercial potato genotypes Solanum tuberosum L. to Phytophthora infestans (Mont.) de Bary late blight attack

David Rodriguez — 2023-04-24

Potato (Solanum tuberosum L.) cultivation is an important agricultural activity in the Andean region. The late blight Phytophthora infestans (Mont.) de Bary, considered one of the limiting diseases in production, represents a threat to food security and causes losses ranging from 30 to 100% of yield. This research evaluated the response to the disease in four commercial materials widely planted in the department of Nariño. The evaluation was carried out under field conditions, in the municipality of Pasto, at AGROSAVIA's Obonuco research center, with natural inoculum, under a randomized complete block design with four replications. The response variables evaluated were incidence, severity, leaf area index and yield in the commercial categories. The ICA Única variety, reported as highly resistant in 2001, presented damage levels close to 75%, with a yield reduction of 49.88%, caused mainly by low yields of first category tubers, indicating a loss of its level of resistance, with damage levels similar to the highly susceptible control Diacol Capiro, which presented 100% of the area with symptoms of the disease and a reduction of 89% in yield. The genotypes Pastusa Suprema with disease tolerance characteristics and Superior showed the best performance with a severity level of 30% in each case and yield reductions of 30.5% and 40.92%, respectively. The results highlight the importance of these genotypes and their role as pillars in the integrated management of the disease through the planting of varieties with favorable behavior against the disease.

The Impact of Agricultural Credit on Banana cultivation in Valle del Cauca, Colombia

Javier Rivera-Acosta — 2023-05-05

This study aimed to explore the use and effect of agricultural credit disbursed from banks and financial institutions on banana yield in farmers from Valle del Cauca (Colombia) using data from the National Agricultural Census (2014). Additionally, it evaluated whether the effect of credit differs according to the items in which the farmer prefers to invest. For this purpose, because credits are not granted randomly, this research used the Propensity Score Matching (PSM) methodology to manage selection bias. Initially, it was found through the probit model that having one's own agricultural machinery, using chemical fertilization to improve soil fertility, not belonging to an ethnic minority, and having some type of basic or higher education, increases the probability of obtaining an agricultural credit. On the other hand, the results suggest that credit has positive and significant effects on crop yield (6.2%), but the effect is greater if it is invested in land purchase and post-harvest processes, with an increase of 39% and 37% in yield, respectively. On the other hand, this study also suggests that, if credit is invested in items not related to agricultural activity, yields can be affected with a 10% reduction. Finally, it is recommended that a public policy be implemented to encourage greater participation of banana farmers in Valle del Cauca in agricultural credit programs, given their low participation (10%) despite the high acceptability rate (86%).

Effect of microencapsulated Lactobacillus reuteri under simulated gastric conditions and its inhibition on Listeria monocytogenes

Henry Armando Jurado — 2023-04-15

Food-borne diseases (FDB) are responsible for causing approximately 600 million illnesses and 420,000 deaths per year. Biologically related FBDs are typically associated with ubiquitous microorganisms, with bacteria such as Li. monocytogenes, Escherichia coli, Salmonella and Staphylococcus aureus being frequently implicated. The use of probiotics is limited by adverse conditions, that can impair the stability of La. reuteri and the evaluation of its probiotic properties and effects on pathogenic bacteria. Therefore, it is crucial to develop effective strategies to protect probiotics during their use. This study was conducted aiming to determine the effect of microencapsulation by spray drying technique on the probiotic viability of La. reuteri on Li. monocytogenes under simulated gastric conditions. The research involved reconstituting, planting, and inoculating La. reuteri and Li. monocytogenes; determining fermentation kinetics; conducting spray drying microencapsulation; studying and characterizing of microencapsulation; testing for exopolysaccharides production; conducting temperature tests; assessing exposure to gastric conditions; and conducting antibiotic susceptibility and inhibition tests. Such investigations allowed the establishment of the exponential phase in Probiotic (PRO) culture medium at 18 h and in De Man, Rogosa and Sharpe agar (MRS) medium at 12 h, exopolysaccharide production positive and growth at different temperatures (1.95x10¹³ CFU/ml and 2.16x10¹²CFU/ml), survival against gastric conditions (greater than 10⁸ CFU/ml) and inhibitory effect of La. reuteri on Li. monocytogenes (halos larger than 2 mm). The probiotic La. reuteri microencapsulated in a binary matrix composed of inulin and maltodextrin expresses probiotic properties against Li. monocytogenes, which is responsible for FBD and great stability after undergoing simulated gastric conditions.

Metabolic indicators and their relationship with reproductive efficiency in dairy cows in the high tropics

Gema Lucia Zambrano-Burbano — 2023-04-20

The specialized herds of the high tropics of Nariño are characterized by semi-intensive breeding models, that is, feeding based on grazing and supplementation. The objective was to analyze the milk production of grazing Holstein cows under conditions of the high tropics, taking into account the energetic and protein metabolites, and their relationship with the dry matter intake (CMS/Kg/d), the body condition (BC), and the reproductive variables. Three periods of lactation were evaluated, thus, between 4-10 days (P1), 45-55 days (P2), and between 185-200 days (P3). The investigation was carried out in four dairy production farms. The forage supply consisted of a mixture of Lolium hybridum, Cenchrus clandestinus Hoschst ex Chiov, Holcus lanatus and Trifolium repens, plus commercial concentrate. A total of 24 Holstein animals (six per productive system) from three births onwards were used, from which blood samples were obtained to determine: non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), triglycerides, cholesterol, glucose, total protein (PT), and blood urea nitrogen (BUN). The results showed that milk production during P1 is influenced by CC and body weight (Kg) by +0.04 liters of milk per unit of change in this variable. In P2, the positive incidence variables were PT, BUN, glucose, NEFA, BHB, triglycerides, and cholesterol, and in P3, the increase in CMS made it possible to show that as lactation progresses in more than 180 days, the animals substantially improve their body condition; likewise the NEFA and BHB indicators are related to a better reproductive response.