Maestría en Agronomía Mención Cambio Climático
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Item Bioecología de Bactericera cockerelli (Sulc.) en el cultivo de papa (Solanum tuberosum L.) en las provincias de Tungurahua y Cotopaxi(2020-09) Manobanda Moreta, Alexandra Maribel; Vásquez Freytez, Carlos LuisThe potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Psyllidae) is considered a pest in several solanaceous species, native to North America and currently it has become more relevant in recent years due to its capacity to invade in various geographical areas, its wide range of host plants and, mainly due to their ability to transmit pathogens to plants they feed on. Given that this species has been recently reported in the country, the present study evaluated the biology, geographic distribution and intra-plant distribution of B. cockerelli in potato crops in the provinces of Tungurahua and Cotopaxi. Biology was studied in potato leaves variety Super Chola under laboratory conditions (21.2 °C and 49.6% relative humidity). Additionally, samplings were carried out in 14 localities belonging to five cantons of the Tungurahua province (Ambato, Tisaleo, Mocha, Quero and Pelileo) and in five localities of the canton of Salcedo (Cotopaxi province). The life cycle of B. cockerelli showed an average total duration of 22.93 days with a mortality rate during the egg phase with 59.6%, while in the first and fourth nymphal instars only 4.25% of mortality was verified, respectively. Regarding geographical distribution, the plague was detected in cantons of Ambato and Píllaro (Tungurahua), in which the potato psyllid was found in 7 of 14 sampled localities, representing 50.0% of the areas considered in sampling. In canton of Salcedo (Cotopaxi), it was found in three of the five sampling locations, representing 60% of positive cases for the presence of the pest. This verified distribution in the sampled areas seems to be related to the height above sea level, since the species was not found in those locations with heights close to 3,000 meters above sea level. Regarding the intra-plant distribution, wide variability was observed in the spatial distribution in the different plant strata (upper, middle and lower), which suggests that the pest shows no preference to select the substrate for oviposition and feeding. The results obtained in the present investigation lay the foundations for thexv bioecological studies of B. cockerelli in the region, however, it is suggested that similar studies be carried out to evaluate other bioecological aspects of the pest.Item Modelo predictivo del impacto del cambio climático sobre la distribución y abundancia de una especie de noctuidae asociada con el cultivo de maiz (Zea mays)(2020-10) Telenchana Paucar, Norma Yolanda; Vásquez Freytez, Carlos LuisIn Ecuador, the maize yield has shown a trend to decrease due to the effect of the misuse of seeds and the attack of pest insects, such as the fall armyworm (Spodoptera frugiperda), stem borer (Dialraca spp.) And the false meter (Mocis latipes); but there are also other potential secondary pests such as the earworm or earworm (Heliothis spp.), cutworms (Agrotis spp.). In the present study, an attempt to establish e relationship between the climatic parameters with the phenology of Agrotis sp. as well as its abundance and incidence in corn plantations. The biology of Agrotis sp. in maize leaves was studied under laboratory conditions. On the other hand, data about pest’s incidence and severity of damage, as well as the historical data from 2017 to 2019 on temperature, relative humidity and precipitation were subjected to a Principal Component Analysis. For this purpose, for each year, a matrix was constructed with the data of each of the variables temperature, relative humidity, precipitation, altitude, percentage of incidence and severity for each of the samplings carried out in each canton (201 in the 2017, 218 in 2018 and 263 in 2019). The results showed that the total development time (egg-adult) of Agrotis sp. reared on maize leaves took an average of 87.3 days, under temperatures that ranged from 18.5 °C during the egg stage and then it increased to 22.7 °C at the end of the development cycle (pupal phase). According to the Principal Component Analysis, the variability of the climatic data was explained by up to 76.81, 75.77 and 79.20% through the first three components from the data of 2017, 2018 and 2019, respectively. In the years 2018 and 2019, the first axis had a greater significance also for the variables precipitation and relative humidity, while the second axis was mainly explained by percentage of incidence and percentage of severity, indicating that the ordering of the given sampling points on the second axis, it was quite related to the incidence percentage and the severity percentage. Finally, rain, relative humidity and temperature showed a second-degree polynomial relationship with the severity and incidence of Agrotis sp. in corn plantations planted in the Sierra region during the years 2017-2019. This study constitutes a first approach to the study of the relationships between the climatic parameters and the populations of Agrotis sp. in corn. More extensive studies are required in other regions of Ecuador in order to achieve a better understanding of the climate-plant-pest dynamics.Item Predicción de la incidencia del cambio climático sobre el daño potencial de Phthorimaea operculella (Zeller) en el cultivo de papa (Solanum tuberosum) en Tungurahua(2020-09) Corrales Gutiérrez, Paúl Andrés; Vásquez Freytez, Carlos LuisThe potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gellechidae) is considered a key pest in potato crops due to damage caused by larvae by drilling tunnels in tubers and leaf and stem mines. Currently this pest species is widely distributed in all the main potato growing areas worldwide due to the difficulty of establishing effective quarantine measures and, on the other hand, the effect of the change, which has caused the pest to occur in more than a hundred countries. In this study, an attempt was made to design a predictive model on theItem Predicción de los efectos del cambio climático sobre el daño potencial de una especie de cogollero en el cultivo de maíz (Zea mays) en la provincia de Tungurahua(2020-09) Carranza Arévalo, Galo Eduardo; Vásquez Freytez, Carlos LuisThe fall army worm, Spodoptera frugiperda (Lepidoptera: Noctuidae) is a pest species native to America and is distributed throughout the continent. Because of climate change, this species has recently become an invasive pest in Africa and Asia, posing a serious threat to corn cultivation. In the present study, an attempt to design a predictive model on the impact of climate change on the level of damage and incidence of the fall armyworm was made in the Ecuadorian Andean region. The model was based on establishing multiple and simple correlations between climatic factors (temperature, precipitation, and relative humidity) and the incidence and severity of the pest, using R language. According to the regression analysis, no significant correlation was detected. between climatic variables and damage and incidence of S. frugiperda. However, the severity level showed a quadratic trend with the climatic variables, being more pronounced with relative humidity and temperature, while the effect of precipitation was milder, the incidence showed a quadratic relationship with relative humidity with increases between humidity levels between 78 and 84%, but in relation to temperature, the incidence showed a tendency to decrease with decreasing temperature. While with precipitation, a very slight trend was observed to increase with precipitation levels around 200 mm / month. Based on the results obtained, it is suggested to evaluate predictive models that consider evaluations of climatic variables (minimum and maximum temperatures, precipitation) differentiating at various times of the day (morning, afternoon, night), in order to be able to carry out more adjusted models and also repeat this analysis considering data from the Amazonia and Costa region in order to verify the fit of the models proposed in this investigation