The use of pesticides on maize crops during and after harvest constitutes a serious health and environmental risk if its prevalence remains during the consumption line. Therefore, the proper determination of the residues of such substances is critical for minimizing the negative impact of pesticides on health and quality of agricultural products. The aim of this study was to evaluate the multiresidual extraction methodology QuEChERS (“Quick, Easy, Cheap, Effective, Rugged, Safe”) as an economic alternative with easy implementation for the analysis of 10 pesticides in floury white corn (Zea mays). Two variants of this method were tested: the original non-buffered method and the official method AOAC 2007.01 with acetate buffer. Analyzes were carried out by gas chromatography with electron capture detector (GC-ECD). Co-extractives percentage and moisture in the final extract were compared, and a check in terms of accuracy, linearity, accuracy, and sensitivity matrix effect was made. Implementation of the original method permitted to obtain cleaner extracts and more consistent and appropriate (overall average between 71,4 – 111,6% with coefficients of variation less than 9,2%) recovery percentages. Additionally, linearity (r> 0,9892) and limits of detection and quantification below the maximum residue limits established by the European Commission (10 to 50 mg kg-1) were also obtained, which makes this method a good choice to routinely quantify the residual effect of the assessed pesticides in the matrix of work.

Andean potato weevil Premnotrypes vorax Hustache is a very important potato pest in Colombia, sometimes causing until 100% of damage. The objective of this research was to evaluate native isolates of Beauveria spp. against P. vorax In vitro. Entomopathogenetic isolates were obtained from infected larvae and adults of P. vorax, Tecia solanivora, Phthorimaea operculella, Aepytus sp., Hypotenemus hampei and Rynchophorus palmarum. Five of eigth isolates (Bv01, Bv02, Bv05, Bv07 y Bv08), with mortality higher than 60% and greather conidia production, were selected in vitro.. The efficacy of each isolate was evaluated on 10 P. vorax larvae. Larvae were disinfected, and submerged in a suspension of 1x107 espores.mL-1. Mortality was assessed each 48 hour during 16 days. A completely randomized design, with six treatments and four replicates was used. All isolates reached an accumulative mortality of 100%, sixteen days after inoculation.. However, the isolate Bv07 showed the highest entomopatogenic activity against P. vorax In vitro.

Yogurt is a food produced by bacterial fermentation of milk that is beneficial to human health. The tuber rubas (Ullucus tuberosus) is a good alternative to human nutrition; however, this food is underexploited and its consumption is limited to a small areas in South America. It is necessary to diversify its consumption through the development of new products based on this tuber. The objective of this work was to develop a yogurt based on rubas. A yogurt prepared based on a rubas concentrate was compared to a regular yogurt without rubas. pH, acidity and syneresis were measured and sensorial, microbiological and proximal analysis were performed during four weeks. Acidifying bacterias were able to grow in rubas yogurt. Sensory evaluation showed that the rubas yogurt had good acceptability. pH, acidity, and the values of the proximal analysis were similar to the regular yogur. However, Syneresis values were lower in yogurt with rubas. Rubas tuber is a good alternative to prepare yogurt.

El gusano blanco (Premnotrypes vorax Hustache.) es una plaga clave en el cultivo de papa en Colombia, debido a las pérdidas en calidad del tubérculo las cuales pueden llegar hasta el 100% dependiendo del nivel de población y manejo del cultivo. La investigación tuvo como fialidad evaluar in vitro aislamientos autóctonos de Beauveria sp. sobre P. vorax . Los aislamientos fueron obtenidos de larvas y adultos infectados de Premnotrypes vorax, Tecia solanivora, Phthorimaea operculella, Aepytus sp., Hypotenemus hampei y Rynchophorus palmarum, colectados en campo y aislados con técnicas In vitro. De ocho aislamientos obtenidos de Beauveria sp, se seleccionaron cinco (Bv01, Bv02, Bv05, Bv07 y Bv08) por presentar un porcentaje de mortalidad superior al 60% sobre larvas de P. vorax. La evaluación de efiacia se realizó en diez larvas de P. vorax . Las larvas se desinfectaron y sumergieron en una suspensión de 1x107 esporas.mL-1, se realizaron observaciones por 16 días, cada 48 horas evaluando porcentaje de mortalidad. Se empleó un diseño completamente al azar, con seis tratamientos y cuatro repeticiones. Los resultados mostraron que 16 días después de la inoculación, se presentó el 100% de mortalidad de las larvas para los cinco aislamientos, siendo el aislamiento Bv07 el que presentó la mayor actividad patogénica sobre P. vorax In vitro.

Los sistemas avícolas destinados a la producción de pollo de engorde se caracterizan por manejar altas densidades en búsqueda de un mayor rendimiento productivo de carne por área de confinamiento, situación que favorece el estrés animal y por ende los bajos rendimientos zootécnicos; teniendo en cuenta que el empleo de probióticos en la alimentación animal es una alternativa para mejorar los índices de producción y reducir el uso de antibióticos promotores de crecimiento, se planteó en esta investigación evaluar el efecto de un consorcio de microorganismos probióticos, Bacillus clausii, Saccharomyces cerevisiae y Lactococus lactis sobre la ganancia de peso y conversión alimentaria en pollos de engorde. Los probióticos se administraron en el agua de consumo a razón de 1x108 UFC de cada microorganismo a razón de 2 mL g-1 de alimento ofrecido, a los 10, 20 y 30 días de crecimiento contados a partir del día dos de vida del animal. El pesaje de los animales se realizó a los 10, 30, y 42 días de producción. Los análisis estadísticos mostraron diferencias significativas con p<0.05 entre los dos tratamientos, evidenciando en la población suplementada con probióticos una ganancia de peso en promedio de 65,97 g/día, conversión alimentaria de 1,74 y mortalidad de 0%. Estos datos sugieren que los probióticos tienen un efecto positivo sobre el aumento ganancia de peso y conversión alimentaria en los pollos de engorde.

La extracción de almidón de tubérculos de ñame se dificulta por la presencia de un material gelatinoso (mucílago), que obstaculiza la sedimentación del almidón y altera las características del mismo. Por lo cual, el presente trabajo tuvo como objetivo evaluar un proceso de burbujeo continuo, por inyección de aire, para extraer y recuperar almidón y mucílago de D. alata y D. rotundata. Cuatro relaciones ñame/agua (1/4, 1/5, 1/6 y 1/7) p/p y tres períodos de operación (30, 60 y 90min) fueron usados bajo un diseño experimental factorial. Se determinó que el proceso de extracción de almidón y mucílago es dependiente de la relación ñame – agua y tiempo del período de operación, existiendo diferencias significativas en las operaciones en las cuales se empleó un tiempo de 60 minutos y se adicionó 6 L de agua por kilogramo de ñame. También se observó, que la mayor extracción de almidón se presentó en D. rotundata, mientras que la mayor cantidad se mucílado se extrajo en D. alata.

Yogurt is a food produced by bacterial fermentation of milk that is beneficial to human health. The tuber rubas (Ullucus tuberosus) is a good alternative to human nutrition; however, this food is underexploited and its consumption is limited to a small areas in South America. It is necessary to diversify its consumption through the development of new products based on this tuber. The objective of this work was to develop a yogurt based on rubas. A yogurt prepared based on a rubas concentrate was compared to a regular yogurt without rubas. pH, acidity and syneresis were measured and sensorial, microbiological and proximal analysis were performed during four weeks. Acidifying bacterias were able to grow in rubas yogurt. Sensory evaluation showed that the rubas yogurt had good acceptability. pH, acidity, and the values of the proximal analysis were similar to the regular yogur. However, Syneresis values were lower in yogurt with rubas. Rubas tuber is a good alternative to prepare yogurt.

For fertilization of crops with boric acid (H3BO3), the use of material with capacity of charge (boron retention) and discharge (boron release) has potential applications in the development of fertilization systems and in the treatment of irrigation water. This study sought to obtain a composite material from polyurethanes (PUs) and N-(4-vinylbencil)-N-methyl-D-glucamine (VbNMDG) by using the technique of interpenetrating polymer networks (IPN), with potential applications in the development of boron fertilization systems. To that end, several PUs were synthesized from an isocyanate (methylendiphenyl-isocianate, MDI) and polyols with variable molecular weight (ethylene glycol, glycerol and manitol). PUs were used as a support matrix and a second network was synthesized by free radical polymerization of VbNMDG, which was previously synthesized by nucleophilic substitution between 4-vinylbenzyl chloride and N-methyl-D-glucamine. Capacity of retention and release of boron were evaluated by batch experiments and the quantification of boron concentration was estimated using azomethine-H method. Results suggest that IPNs obtained from manitol have a larger retention capacity of H3BO3 than those obtained from ethylene glycol and glycerol. Retention properties of IPNs increase as the R-OH/H3BO3 ratio increases. The study concluded that IPNs can be obtained from PUs and poli(VbNMDG) using dioxane as solvent.

The use of polymers in soils have been mainly focused in the increasing of water storage capacity and efficient water using, increasing of infiltration rate, reduction of irrigation frequency, erosion control, decreasing of lost by runoff and increase its usefulness for planting crops. The aim of this work was to determine the effect of polyelectrolyte (PEL) addition on chemical composition of soil aqueous phase of acid sulfate soils (ASS). For that, different soil samples were collected and incubated with aqueous polymer solutions: poly(acrilic acid) (PAA), poly(vinyl pyrrolidone) (PVP) and poly(sodium styrenesulfonate) (PSSNa). Effect of PEL was seen to be strongly dependent on chemical nature of functional groups on polymer chains. In the case of PSSNa and PAA, effect of polymer concentration was characterized by the immobilization of ions; whereas for PVP a solubilization effect was observed. Results indicate that interaction between chemical species from aqueous phase and polymer functional groups is an important factor that should be considered. In addition, effect of polymers is influenced by pH and organic matter contents.

In the past five years in the department of Nariño, the increase in severity of damage produced by oidio (Erysiphe polygoni) in vetch has been observed, which produces loss of yield crop between 20 and 40%. The improved varieties present susceptibility to the pathogen. This research was conducted in SENA’s Lopez Farm in Pasto - Colombia, in two phases. In the first phase, 90 lines of pea were evaluated (Pisum sativum L.) along with the gen afila for yield and reaction to powdery mildew (Erysiphe polygoni) under natural inoculate conditions. The assessed lines were obtained by simple crosses and backcrosses between the parentals Andina, San Isidro, and Sindamanoy, and the donor genotypes of the afila gen: Dove, ILS3568 and ILS3575. A random augmented blocks design was used. Results showed that 10% of the materials were resistant to powdery mildew, 20% were moderately resistant, 60% were moderately susceptible, and 10% were susceptible. From these materials, 19 resistant and moderately resistant genotypes with the highest yield were selected, which were assessed in the second phase for yield and components. For green pod yield and dry grain, 84% and 68.4% of the tested lines reached similar averages than those in the commercial controls Sindamanoy and Andina. The selected lines with the gen afila recovered 88,42% of the yield and yield components from their parents Andina, San Isidro, and Sindamanoy.