vol. 12 núm. 1 (2021)

Contextualization: Fusarium graminearum is a field microorganism that affects grasses and causes great losses, particularly to rice crops. To counter these phytosanitary problems, excessive amounts of pesticides are applied, causing damage to health and the environment. An alternative is to plant extracts with a high content of bioactive compounds.   Knowledge gap: The pyrogallol tannins contained in Caesalpinia spinosa pods have biological properties, Fusarium graminearum's micellial growth inhibition is effective at low concentrations of UFC/ml.   Purpose: Therefore, the objective in this research was to determinate in vitro the antifungal activity of tare phenolic compounds (Caesalpinia spinosa) against Fusarium graminearum.   Methodology: Firstly, the phenolic compounds extracted by maceration and heating (60 °C) through water and ethanol-water mix, the phenolic compounds content in the extracts determined by Folin-Ciocalteu method. Secondly, a Fusarium strain obtained from a rice culture isolated and identified by taxonomic keys, after cell suspensions made with concentrations 10⁷ and 10⁶ UFC/ml. For in vitro evaluation, a disc with an inoculum of each suspension placed in a culture medium containing C. spinosa extract.   Results and conclusions: Consequently, the aqueous extract by heating with a content of 5.88 g gallic acid/100 g dry sample inhibited 30 and 70% of mycelial growth of Fusarium graminearum with a concentration of 10⁷ and 10⁶ UFC/ml. Phenolic compounds of Caesalpinia spinosa have properties of interest for the control of Fusarium graminearum and can be tested in vivo, in the greenhouse.

Introduction: Ochroma pyramidale is a species with high restorative potential and adapts easily in disturbed areas; however, seed germination is affected by being orthodox and experiencing dormancy. Knowledge gaps: Variation in germination capacity between different treatments and different environmental conditions. Objectives: To evaluate the germination percentage of O. pyramidale seeds by means of different chemical scarification methods. Methodology: An experimental design of three blocks, three replicates and 15 test units was applied. The treatments were: T1 (hot water at 80°C), T2 (0.5% NaCIO), T3 (1.0% NaCIO), T4 (2.0% NaCIO), T5 (1% HCl). Results and conclusions: Germination of O. pyramidale seeds in all treatments started on the fourth day after sowing with some differences in germinated seeds between treatments with respect to the first day of germination with some variations between treatments. The highest percentage of germination occurred in treatment 1 (T1) with 88 seeds (59%), followed by treatment 2 (T2) with 65 (43%). Treatment 1 (water 80°C) had the greatest influence on the germination of O. pyramidale seeds. Therefore, boiling treatments not only contributed to increase germination, but also the seeds achieved a higher germination rate.

Contextualization: Fusarium wilt is the most important pea (Pisum sativum L.) disease in Pamplona, where indiscriminate use of chemicals is applied.   Knowledge gap: There are no scientific reports of application or efficacy of biocontrollers for Fusarium wilt in pea in this municipality.  Purpose: This research aimed to evaluate biological alternatives for the control of Fusarium wilt in pea cultivation in Pamplona, Norte de Santander in order to give recommendations to farmers about its possible use and to project future research.  Methodology: An experimental design was carried out where six treatments were evaluated: three with biopreparations commercialized by the Association of Agricultural Producers (ASPAGRO), separately and in combination, a commercial antagonist (Trichoderma harzianum), a chemical treatment with benomyl, and a negative control. Fusarium oxysporum was identified as the causal agent of pea wilt in Pamplona. The commercial product based on Trichoderma harzianum was shown to reduce the incidence of the plant disease and the Area Under the Curve of Disease Progress (AUCPD) of Fusarium wilt in pea was similar to Benomil.  Results y Conclusions: The analysis of variance for the incidence of wilt showed a difference between the treatments, the evaluation moments and between the interactions of the treatments and the evaluation moments, as well as between treatments for the incidence and the AUCPD at the end of the crop cycle. Compared to negative control, ASPAGRO's biopreparations of Caldo Rizósfera and Microorganismos de Montaña reduced the incidence of the disease and the AUCPD. The three biopreparations achieved to reduce the incidence of wilt. Nevertheless, the yield decreased by values close to 10, 25, and 30% in the treatments with Trichoderma, Caldo Rizósfera, and Microorganismos de Montaña, respectively, in comparison of benomyl. Therefore, the first two biological means are considered the best options for the control of Fusarium wilt in peas in Pamplona, however research should be carried out to validate them in larger areas.

Contextualization: The pests, diseases and weeds control in the bean crop production, is one of the most representative crop at the economic level in the Sibundoy municipality, it is characterized by the use of agrochemicals. The problems that these generate must be addressed from its origin, management and final disposal of post-consumer waste. Research gap: The phytosanitary products and residues management in agricultural production has generated environmental and human health problems over the time. The use, storage, type of products, residues final disposal and safety in the application carried out by agricultural producers, it is a little evaluated subject in the region. Then, it is advisable to study the current situation of this problem, which allows taking decisions and proper handling measures of this type of product in the agricultural systems. Purpose: The research objective was to study the management, classification and collection of phytosanitary products in the beans cultivation (Phaseolus vulgaris) in Sibundoy Putumayo Colombia. Methodology: It was descriptive, based on the collection of primary and secondary information, which allowed the different aspects characterization, qualitatively and quantitatively. The analysis was carried out in two phases. The first one was direct observation and field surveys application, handling identification, waste final disposal and risk perception. The phase two included the agrochemical containers collection and classification used by farmers for 6 months. The containers classification was carried out according to the following parameters: trade name, active component and toxicological category. In addition, it was carried out the waste weighing generated in this agricultural activity. The information collected was an important input for conducting a multiple correspondence analysis. The investigation diagnosed the handling that farmers give to pesticides during the cultivation productive cycle, which is 6 months, where it was identified the inappropriate use from its reception, handling and final disposal. Results and conclusions: In total, they were collected 554 containers, 35% correspond to insecticides, 25% fungicides, 20% herbicides and 18% without identification. The farmers total who were surveyed were 51 people, 43% of them collect the containers. In the conglomerate analysis, it was obtained Cluster IV where are grouped the most relevant data. Finally, it is concluded that the agrochemicals use with respect to their application and final disposal is characterized by their inadequate management, in aspects such as dosage, storage, and operator safety, which threatens the ecosystems balance and the farmers health.

Contextualization: The noise exposure assessment is an essential component of hearing loss prevention programs to recognize vulnerable workers, to propose control measures and / or to evaluate the measures implemented. Knowlegdge gap: In Colombia, there is a limited number of works that address noise exposure and its assessment. Purpose: Occupational noise exposure in the operating area of two microenterprises in the city of Neiva was evaluated by dosimetry and sonometry. These companies are dedicated to the commercialization of chipboard using specialized machines such as vertical saws and veneers. Methodology: Initially, a diagnosis of working conditions was made; later, noise measurements were carried out following the work-based strategy pursuant ISO 9612-2010. Results and conclusions: The equivalent sound pressure levels (73,0 and 82,4 dB (A)) registered by the sonometry system are similar to those reported in carpentry workshops and furniture factories. The dosimetry results reveal that the vertical saw and the veneer machine operators are exposed 8 hours daily to noise levels between 88,50 and 89,9 dB (A), which exceed the permissible limit value (85 dB), as stipulated by resolution 1792 of 1990. However, the chipboard microenterprise operators evaluated were not overexposed to noise thanks to the attenuation brought by the hearing protectors used.

Contextualization: The cowpea bean is important for the food security of the Caribbean region of Colombia, where creole genotypes of low-yielding per hectare, susceptible to biotic and abiotic factors, and low mineral content are cultivated.   Knowledge gap: The agronomic performance and mineral accumulation in the grain of new genotypes obtained by individual selection are unknown. Purpose: To evaluate the agronomic performance and nutritional quality of eight advanced homozygous lines of cowpea beans from the breeding program of the Universidad de Córdoba, Colombia. Methodology: The experiment was established between April and July 2014, under a randomized complete block design with nine treatments, including the Criollo-Córdoba as control, with four replications. The characteristics pod length, grain length and width and, pod weight, number of seed per pod, weight of one hundred seed, grain yield per hectare, iron, zinc, phosphorus and protein content were evaluated.   Results and conclusions: The genotypes showed significant differences in pod weight, number of seed per pod, grain length, grain width, grain yield per hectares, iron, phosphorus and protein content in the grain. Lines L-042 and L-047 were the ones with the best agronomic performance and the highest nutritional quality. Principal component analysis and biplot allowed to identify the L-014 and L-047 genotypes associated with grain length, pod length and pod weight, while L-006, L-042 and CR-CO, are associated to grain width, weight of one hundred seed and grain yield per hectare, which is important for genetic improvement programs for this species.

Contextualization: Equine piroplasmosis is a tick-borne disease, caused by protozoa Babesia caballi and Theileria equi. The animals affected have different clinical signs that include anemia, fever, icterus and depression. Infected equids with T. equi can carry the hemoparasite for life, while the infected animals with B. caballi can disseminate for a few years until finally get rid of the infection.   Knowledge gap: In Colombia there are few studies on the isolation and identification of hemoparasites in equines using molecular techniques such as PCR. Among these parasites are Babesia caballi and Theileria equi, causative agents of Piroplasmosis a disease notifiable by the World Organisation for Animal Health.   Purpose: The aim of this study was to identify equine piroplasmosis using polymerase chain reaction in a farm located in Jamundí (Valle del Cauca).   Methodology: In a total of 20 animals, divided in two groups, (animals in stable and animals in grassland) was collected peripheral blood to perform smear stained with Wright. Also, other samples were sent to the laboratory for molecular diagnosis.   Results and conclusions: All samples with Wright were negative for hemoparasites, however, by PCR it was possible to identify piroplasmosis. Conventional PCR was a sensitive and reliable method to diagnose the disease in an asymptomatic individual. More studies should be carried out in this region on Babesia sp. to identify possible predisposing and causal factors, as well as to improve the measures for its prevention, control and treatment.

Contextualization: This study identifies that the city of San Juan de Pasto, especially its central and southeastern area, present a significant pressure on environmental resources, due to a higher population density, generating various environmental problems due to the urbanization process. Knowledge gap: Such situation gave rise to the development of this research, to formulate strategies that contribute to the improvement of urban environmental quality in commune three, by obtaining urban environmental quality indicators, estimating environmental quality in the area of study and formulation of alternatives that increase urban environmental quality and prevent environmental impacts. Purpose: The specific objectives of the study were: Identify environmental quality indicators, estimate the urban environmental quality index and propose alternatives to improve urban environmental quality in commune three, San Juan de Pasto. For this, the urban environmental quality index, a methodology designed by the Ministry of Environment and Sustainable Development (2016), was applied as an instrument to assess environmental sustainability in cities and prioritization of alternatives was carried out through of the method; multi-criteria prioritization matrix. Results and conclusions: The urban environmental quality index value for commune 3 obtained a rating of 50.5, which indicates an average urban environmental quality, with Air Quality and the percentage of urban population located in high threat areas being among the most representative, obtaining a Very high and very low rating respectively. The prioritization of alternatives led to the study of two strategies; a modular green terrace system and a sustainable mobility strategy - Public bicycle system, which would improve the environmental quality of the study area. This process concluded that the application of the urban environmental quality index proposed in previous research has a moderate viability in the application at the strategic level of the commune.

Contextualization: The increase in wheat production has caused pathogenic diseases to appear more frequently due to the implementation of monoculture. The Septoriosis or stain of the wheat leaf caused by Zymoseptoria tritici causes a decrease in the photosynthetic area causing losses in grain yield ranging between 17% and 50%, depending on the phenological state in which the infection occurs.   Knowledge gap: The most frequent method for controlling the disease is the application of chemical synthesis products, which has generated resistance in the population of the fungus and contamination of the agroecosystems. For this reason, new management alternatives are being sought, such as the activation of systemic resistance. Induced by the application of salicylic acid that causes physical, chemical and molecular changes such as lignification or the induction of various proteins related to pathogenesis that does not allow the entry of the hyphae of pathogenic fungi, being a sustainable alternative.   Purpose: The purpose of this research was the evaluation of the effect of salicylic acid on the development of the symptoms of wheat leaf spot caused by Zymoseptoria tritici, and to establish its probable changes on the yield components in cultivars Biointa 3004 and Buck sy 200.   Methodology: The study was carried out at the Julio Hirschhorn experimental station of the National University of La Plata (UNLP), for which the cultivars Biointa 3004 and Buck sy 200 were used, the experimental design was in divided plots with three replications and was constituted by the following treatments: Control, inoculated with Zymoseptoria tritici, treated with salicylic acid and treated with salicylic acid and inoculated with Zymoseptoria tritici. and the tests were carried out in the winter-spring season of 2012 and 2013 and the percentage of pycnidia, the percentage of necrotic area, the number of empty spikelets, the number of grains of the spike, and the weight of 1000 grains were determined.   Results and conclusions: The pycnidia coverage decreased by 45%; the necrotic area, by 40%; in addition, the number of empty spikelets decreased by 4% and the number of grains per spike increased (5%) and the weight of 1000 grains (2%). It is shown that salicylic acid greatly controls the negative effects of the disease and stimulates the yield components, improving the productivity of two cultivars evaluated.

Contextualization: To guarantee the quality of the water in the reservoirs destined to the treatment and supply of drinking water, toxicity analyzes of the water and sediments must be carried out periodically, due to its can be reservoirs of the organic pollutants that during remobilization processes could make those available in the aquatic ecosystems.   Knowledge gap: Because these contaminants concentrations are found in traces (ng/L), it is necessary to use passive sampling methods that allow the accumulation of hydrophobic compounds in semi-permeable membrane devices (SPMDs) for subsequent evaluation.   Purpose: The purpose of this study was to evaluate the toxicity of samples from SPMD-type passive sampling extracts and sediments by the use Microtox® assays using the Vibrio fischeri bacteria.   Methodology: The 24 extracts used in the trial were obtained from semi-permeable membrane devices (SPMDs) previously deployed for 21 days in 6 stations located in the reservoir of the La Fe, Antioquia, in four sampling campaigns. The extracts were tested by Microtox Basic Test medium. The evaluation of the toxicity potential of the reservoir sediment was also analyzed by means of acute toxicity tests with Microtox® applying the Solid Phase Test (SPT) protocol as well as the physicochemical parameters of water such as pH, temperature, electrical conductivity, dissolved oxygen and turbidity.   Results and conclusions: The results of the toxicity tests indicate that the analysis of the extracts of SPMD collected in water reservoir La Fe does not present toxicity, while those fed by sediments presented moderate or low toxicity.

Contextualization: Pseudomonas aeruginosa is capable of producing biosurfactants which have many uses in bioremediation and the production of antiviral, antibacterial, antiparasitic, sporicidal and antifungal agents, among others.   Knowledge gap: This study describes the production of mono and di-rhamnolipid biosurfactants by P. aeruginosa strains isolated from Zea mays rhizosphere and composts in the state of Guerrero, Mexico.  Purpose: The overall aims were to investigate biosurfactant, pyocyanin production, and tolerance to heavy metals and antimicrobial activity capacity than biosurfactants produced from P. aeruginosa strains from corn rhizosphere and compost in Mexico. Methodology: Biosurfactant production was determined based hemolysis on blood agar, blue halos in CTAB-Methylene blue agar, drop collapse test and production of foam on PPGAS broth, the emulsion index (IE24) and antibacterial capacity. The strains were identified by sequence of the 16S rDNA gene and their resistance to heavy metals were also evaluated. Results and conclusions: Two strains isolated from Zea mays rhizosphere (PAM8, PAM9) were the best biosurfactant producers and their extracts showed antimicrobial activity against Grampositive and Gramnegative bacteria. PAM8 and PAM9 showed >30% of cellular hydrophobicity to hydrocarbons, and were capable of emulsifying toluene, cyclohexane, petroleum, diesel and oils. All strains showed the same profile of heavy metal tolerance (As5+ >As3+ >Zn2+ >Pb2+ >Fe3+ >Cd2+ >Cu2+ >Cr6+ in concentrations of 20, 10, 10, 6, 4, 4, 2 and 2 mM., respectively). The isolation of biosurfactant-producing and heavy-metal tolerant bacteria from Zea mays rhizosphere and compost in Guerrero demonstrates the capacity for this region to harbor potentially important microbial strains for industrial or bioremediation applications.

Contextualization: Currently, interest in the production of microalgae has increased due to the different uses of microalgal biomass in some industrial sectors, in addition to being used in the mitigation of greenhouse gases thanks to its high capacity for CO2 capture. Knowledge gap: Being part of the Paris Agreement in 2015, Colombia is committed to reduce its greenhouse gases emissions by 20%, to contribute to the goal set for 2050, for this reason, it must adopt research and action plans focused on this objective. Purpose: the purpose of this study was to evaluate the effect of CO2 induction at different concentrations on the growth kinetics of Chlorella Vulgaris CV_2714A and Scenedesmus Obliquus SOB_001 in a laboratory scale photobioreactor system in a volume of 3.8 L of culture medium (NPK solution + micronutrients). Methodology: The tests were carried out in photoperiods with 12 hours of light and 12 hours of darkness for 5 consecutive days. The completely randomized experimental design whose sources of variation were microalgae species and CO2 dosage (0.2, 6.5 and 12.8 L. day-1) with artificial lighting by a 4400-lumen fluorescent lamp. The cellular concentration was estimated by means of the numerical approximation in the “Neubauer” chamber with the methodology used by Darki et al. (2017), in addition to growth rate and cell doubling time in days according to Andersen, (2005). The data were submitted to analysis of variance and Tukey's mean tests (p<0.05). Results and conclusions: The results in the different tests showed a higher cell concentration in C. vulgaris compared to S. obliquus. Regarding CO2 supply, the 2 species obtained a significantly greater response (p<0.05) at the dose of 6.5 L. day-1, reaching a cellular concentration of 2.59 x 107 cel.ml-1 and 4.62 x 106 cel.ml-1, respectively. These results allow us to conclude that the cultivation of these microalgae associated with the dose of CO2 can favor their rapid growth and biomass production, while also contributing to other studies on the reduction of greenhouse gases.