Tesis Ingeniería Agronómica

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    Efecto del extracto etanólico de Annona cherimola en el control de Oligonychus coffeae (NIETNER, 1861) (ACARI: TETRANYCHIDAE)
    (2017) Gavilanes Gavilanes, Cristian Rafael; Vásquez, Carlos
    Oligonychus coffeae (Nietner) is considered an economic importance pest in coffee trees and other crops from tropical and subtropical regions so that constant methods of control are required. In this study, the acaricidal effect of different extract doses obtained from leaf and seed of Annona cherimola (625, 1250, 2500, 5000 and 10000 mL/L) on mortality rate, oviposition rate and fecundity in O. coffeae females under laboratory conditions. The effectiveness of extracts was evaluated using the residual contact technique in rearing units using coffee leaf discs. Mortality, oviposition and fecundity of O. coffeae females were affected by type and concentration of extract. Highest mortality rate was achieved with the application of seed extract. Additionally, it caused oviposition decrease by 46.7 or 82.5% with the seed extract at 625 mL/L and 10,000 mL/L, respectively, while the leaf extract, decreasing varied from 29.9 to 62.0% at 625 and 10000 mL/L. Seed extract was also more effective in reducing the fecundity of O. coffeae females (28.9 eggs/female), as compared to females treated with leaf extract (36.1 eggs/female). The results showed that cherimoya could be a sustainable alternative for the management of O. coffeae populations in coffee plantations, however field studies are suggested to validate laboratory studies.
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    Evaluación del nivel de daño agronómico de Tetranychus urticae KOCH (Acari: Tetranychidae) en variedades de Fragaria spp.
    (2019-01) Toapanta Yanchatipán, Nelly Janneth; Velástegui, Giovanny
    This research work was carried out to evaluate the damage produced by different densities of Tetranychus urticae in strawberry varieties in the Experimental Farm Querochaca, propriety of the Technical University of Ambato, Faculty of Agricultural Sciences. There was a total of 12 treatments with 3 varieties (Albión, Festival and Monterrey) with 4 population densities (0.2, 4 and 8) and 4 repetitions, the experimental design of completely randomized (DBCA) was used, the data were subjected to ANOVA using Tukey tests of significance of 5% in the Statistix program. Of the 12 plants / treatment, 5 plants were selected at random for treatment for infestation with mites in different population densities, after which the data were collected in a 7 day interval and registered the population of mites, the damaged leaf area, the affected numbers of flowers and fruits in a period of 40 days. Once it reached 40 days we proceeded with the analysis of the quality of the fruit, of the plants analyzed above, 10 fruits / plant of each treatment were harvested and the length, width, weight, pH, ° Brix and hardness was registered. Different varieties of strawberry evaluated showed significant differences in the number of flowers / plant, number of fruits / plant and leaf area damaged by the effect of the density of the mite. With relation the number of flowers per plant, the greatest reduction occurred when the Festival and Monterrey plants were infested with 8 mites / leaves, in which 17.9 and 27.2% reduction in the number of flowers was reported this did not happen with the Albión variety because exposed to densities of 4 and 8 mites / plant showed a greater number of flowers. Regarding the reduction in the number of fruits per plant was more evident in the Monterrey variety where it reached 50 to 31.3% less fruits, while in the Festival variety the reduction was only 8.9%. With regard to the number of fruits / plant the results obtained they do not show any significant difference. As for fruit quality the variables weight, length and hardness of the fruit weren’t affected by the feeding of the mite. Contrary to the width and º Brix of the fruit the Albion variety wasn’t affected while in the Festival and Monterrey varieties the highest values were obtained in plants infested with 4 and 8 mites / leaf and caused a decrease in the total solids in the fruit. Contrary the pH was only affected in fruits of the Albión showed a tendency to decrease.