Ingeniero Agronomo
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ItemHongos de la semilla de maíz (Zea mays L.) y su sensibilidad in vitro a fungicidas(Ingenieria Agronomica, 2023)Fungi are the main cause of crop losses worldwide, and corn seed can play a fundamental role in the dissemination of some diseases, a factor that should be considered for their adequate control. The aim of this research was to identify phytopathogenic fungi in corn (Zea mays L.) seed and their in vitro sensitivity to commercial fungicides at different doses. The experiment was carried out in the laboratories and greenhouses of the Instituto Nacional de Investigación Agropecuarias, Portoviejo Experimental Station (INIAP-EEP). The microorganisms present were isolated from stored seeds in Petri dishes with PDA. Subsequently, the colonies obtained were purified and morphologically identified using taxonomic keys. In vitro sensitivity was carried out in order to evaluate mycelial growth inhibition, for which na experiment was set up using a DBCA design with thirteen treatments (four fungicides at three doses) Ipodrione 50 PM (0.8; 1.0; 1.2 gr/cc), Fludioxonil 2.5% w/v (0.6; 0.8; 1.0 gr/cc), Fludioxonil 2.3% w/v+ Metalaxyl-M 1.9% w/v (1.0; 1.2; 1.4 gr/cc), Control Carboxin 17%+ Thiram 17% (0.4; 0.6; 0.8 gr/cc) plus na absolute control, using four replicates per treatment. Comparison of means was performed using Tukey’s test (P < 0.05). The best treatments from the previous test were used for the control test on seeds inoculated under semi-controlled conditions, for which the seeds were inoculated by immersion in spore suspension at a concentration of 106 conidia per mL. In this case, a DBCA design was used with fourteen treatments (two fungicides at three doses, on seeds both inoculated and uninoculated with the pathogen), plus two absolute inoculated and uninoculated controls, where the variables evaluated (8 days later) were % of healthy germinated seedlings, % of germinated seedlings with fungus, % of non-germinated seeds with fungus and % of non-germinated seeds without fungus. Based on morphological characteristics, 35 of the 50 isolates obtained were identified as Fusarium sp. In the in vitro sensitivity test, only the fungicide (Caboxim 17%+ thiram 17%) was able to completely inhibit mycelial growth of the pathogen in relation to the control. However, for the control test on seeds inoculated under semi-controlled conditions, those with the best results (Carboxim+thiram e Iprodione) in the in vitro test were used.
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ItemRespuestas del maíz (Zea mays L.) a la fertilización orgánica y química durante la etapa de desarrollo vegetativo en la zona de Santa Ana -Manabí(Ingenieria Agronomica, 2023)Maize (Zea mays L.) is one of the most important species in the world, because it is one of the basic foods and with great economic importance, as well as one of the main ones in Ecuador. The main objective of this research work was to evaluate the response of corn to organic and chemical fertilization during the vegetative development stage of the crop. This research work was carried out in the Experimental Campus of the Faculty of Agricultural Engineering. Vea used a Randomized Complete Blocks experimental design with three replicates and 30 experimental units. As study factors were the sources of fertilization: Compost, Urea + Triple Super Phosphate (SPT) + Potassium Chloride (KCl), Compost + Urea + Triple Super Phosphate (SPT) + Potassium Chloride (KCl) and fertilization doses. Chemistry N-P-K of 66-23-30; 132-46-60; 198-69-90 and a control without fertilizer application, in which growth variables, relative chlorophyll content and foliar nitrogen concentration were evaluated. The results determined that there are better responses to organic and chemical fertilization, in the treatments of C+ U+SPT+KCl and U+SPT+KCl with doses of NPK 198-69-90 for most of the variables evaluated with the exception of content. Of foliar N since it did not respond to the tested factors or to the combination of them, the sources much less the tested doses had an effect on the foliar N content.
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ItemEvaluación de los indicadores morfo fisiológicos y el rendimiento del frijol caupí (Vigna unguiculata) con el uso de dos alternativas orgánicas y microorganismos eficientes(Ingenieria Agronomica, 2023)Cowpea bean is a legume with high nutritional value. In Ecuador, in 2021, were cultivated 29,539 ha with a production of 17,717.21 t. In organic fertilization, the main fertilizers used in crops are usually composts and manures, which favor the growth and development of the plant and microorganisms, and vermicompost leachates are Biostimulants that constitute alternatives for sustainable agricultural production. The main objective of this research was to evaluate the morphological and physiological indicators and yield of cowpea using vermicompost leachate, decomposed bovine manure and efficient microorganisms, in an experiment with a completely randomized block design (DBCA) with three repetitions and seven more treatments. the witness. Four applications were made every 15 days after germination until harvest. For the analysis of variance, the TUKEY test at 5% was used. It was demonstrated that the use of bovine manure, leachate from vermicompost and efficient microorganisms induced that the magnitudes of the morphological, physiological and productive indicators evaluated reached values equal to or higher than those obtained with chemical fertilization based on nitrogen, phosphorus and potassium, which shows the potential of these biostimulants in the crop and that the vermicompost treatment of 3 t. ha-1 induced a significant effect, compared to efficient microorganisms, leachates and NPK fertilization on the number and weight of pods and grains per plant, as well as the estimated yield in Kg ha-1 in the bean crop. cowpea
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ItemPROSPECCIÓN DE ENTOMOPATÓGENOS DE Spodoptera frugiperda Smith EN TRES LOCALIDADES DE MANABÍ(Ingenieria Agronomica, 2023)Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is the main pest of maize in America, being its control with synthetic pesticides, in spite of having natural enemies, among them entomopathogens. The objective of this study was to determine the diversity of entomopathogens of S. frugiperda in three locations in Manabí. Maize crops were selected in Estancia Vieja, Lodana and Santa Ana. Three samples were taken from each corn crop to collect the different stages of the insect, which were taken to the Entomology laboratory of the Faculty of Agricultural Engineering where they were placed in rearing chambers to record the diseased stages. The entomopathogens were isolated on PDA culture medium and identified by microscopic observations and morphological characteristics of the microorganism. The diversity of the entomopathogens was obtained using Simpson's diversity index. The incidence of natural control of the entomopathogen was 4% and was only recorded in Lodana. Only one fungus was found, which according to morphological characteristics corresponds to the genus Lecanicillium. The action of the entomopathogen on S. frugiperda occurred only in the larval stage. During this study, the parasitoid Winthemia sp. was found. The diversity of entomopathogens was low and was only recorded in the larval stage of S. frugiperda.
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ItemExtracción de macronutrientes en dos variedades de lechuga (Lactuca sativa L.) bajo sistema hidropónico(Ingenieria Agronomica, 2023)Lettuce occupies a prominent place in the national economy as one of the most demanded and valued horticultural crops in consumer markets. In this context, the objective of this research was to evaluate the extraction and recovery efficiency of nitrogen (N), phosphorus (P), potassium (k), calcium (Ca) and magnesium (Mg) in two varieties of lettuce (crespa and capitata) using a hydroponic system. Treatments consisted of doses of 1; 1.5; 2 and 2.5 ml/L of stock solution, which contained specific amounts of nutrients (46.01 N, 23.4 P, 60.5 K, 39 Ca, 14 Mg, 11.43 S, 1 Fe, 0 0.13125 B, 0.0525 Zn, 0.0625 Cu g/L). Variables such as the concentration of nutrients in leaves, the extraction and the recovery efficiency of N, P, K Ca and Mg were analyzed. The results showed that the highest concentration and extraction of nitrogen in the lettuce leaves was obtained by applying 1 ml of the mother solution, while for P, K, Ca and Mg the highest values were observed with an application of 2 ml of the stock solution. As for the varieties, no significant differences were found in the concentration of P, K and Ca in the leaf, while the crespa variety presented a higher concentration of N than the Mg variety Capitata. On the other hand, the extraction of all the evaluated nutrients was greater for the crespa variety, which suggests that this type of lettuce requires a greater amount of nutrients to reach its maximum yield potential. In terms of nutrient recovery efficiency, it was observed that the low doses (1 ml of the stock solution) showed the highest values, except for phosphorus, whose efficiency was higher with an application of 2 ml of the stock solution. The crespa variety also demonstrated greater efficiency in the recovery of the applied nutrients.