Ciencias Agropecuarias
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Item Efecto del uso de un coadyuvante en la efectividad del extracto etanólico de ajo para el control de oligonychus yothersi (Mcgregor) (Acari: tetranychidae)(2022-09) Tiana Erazo, Álvaro Mauricio; Santana Mayorga, Rita CumandáTetranychidae includes pest species that can inflict economic damage to crops of economic importance worldwide, so they often require control measures. Given its importance, several studies have been carried out to evaluate the efficiency of more environmentally friendly control methods, such as the use of biopesticide products. In the present study, the effect of the use of an adjuvant on the effectiveness of the ethanolic extract of garlic for the control of Oligonychus yothersi was evaluated. The acaricidal activity of the garlic extract was evaluated by the residual contact technique using leaf disks immersed in each of the extract concentrations for 20 s. The use of adjuvant caused a higher mortality rate at 24 h after application, reaching 37.5%, while in the treatments where no adjuvant was used, it reached 30.0%. At 48 hours after application, the mortality rates during these periods were 23.33 and 25.42% with and without adjuvant, respectively, and at 72 hours, rates of 16.67 and 12.92%, respectively, were reached. However, when analyzing the effect on cumulative mortality after 72 h of application, what was observed at 24 h was verified, where the cumulative rate reached 77.50 in the extract with adjuvant and 68.33% when the extract was used. only. Additionally, the garlic extract with adjuvant caused the greatest reduction in oviposition at the highest concentrations (8 and 16% of the extract) with a reduction of 70.80 and 7.03% compared to the control treatment. On the other hand, the observed reductions in oviposition when garlic extract was used alone were smaller, since, with the highest doses, the percentage reduction was 55.3 and 59.6%, respectively. Finally, the greatest reduction in longevity was observed with doses of 4 to 16% of the extract, regardless of whether it was applied with or without adjuvant. The intermediate doses (1 and 2%) were able to cause a reduction in longevity between 27.3 and 35% in relation to the control treatment. The garlic extract showed to have a positive effect in the control of O. yothersi, for which it could be included in pest management plansItem Evaluación de una especie de fitoseido (Acari: phytoseiidae) para el control de Tetranychus urticae (Acari: tetranychidae) en rosa spp(2022-09) Pico Martínez, Christian Alexander; Santana Mayorga, Rita CumandáThe two-spotted mite, Tetranychus urticae Koch, is one of the most important phytophagous mites in agriculture due it is able to feed on a large number of plant species, its wide geographical distribution and the number of cases of resistance to different acaricidal products. In view of its importance, numerous studies have been carried out to evaluate alternative methods of control, such as biological control. In this research, the effect of the prey density (Tetranychus urticae) on the consumption and reproduction rates of Typhlodromalus sp. was evaluated in laboratory conditions. Regarding the predation rate, an increase in consumption was observed as the prey density increased, reaching a maximum of 11.2 eggs and 5.2 individuals/predator, respectively. Similarly, a positive effect of increasing prey density on the reproductive rate Typhlodromus sp. female, measured as the number of eggs laid per female per day, was observed. According to the results, it is possible to conclude that Typhlodromus sp. shows biological attributes that would allow it to increase its population levels accordingly increases in the pest population, which is a desirable characteristic of natural enemies to be included in integrated pest management programs.Item Evaluación del nivel de daño agronómico de Tetranychus urticae KOCH (Acari: Tetranychidae) en variedades de Fragaria spp.(2019-01) Toapanta Yanchatipán, Nelly Janneth; Velástegui, GiovannyThis 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.Item Efecto del extracto etanólico de Annona cherimola en el control de Oligonychus coffeae (NIETNER, 1861) (ACARI: TETRANYCHIDAE)(2017) Gavilanes Gavilanes, Cristian Rafael; Vásquez, CarlosOligonychus 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.