Ciencias Agropecuarias

Permanent URI for this communityhttp://repositorio.uta.edu.ec/handle/123456789/870

Browse

Filters

2021 - 20222

Settings

Subject: search.filters.subject.MCGREGOR

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    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 Cumandá
    Tetranychidae 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 plans
  • No Thumbnail Available
    Item
    Determinación de la variabilidad genética de la región ITS2 en poblaciones de Eotetranychus lewisi (MCGREGOR) en el cultivo de Rubus glaucus Bent (mora)
    (2021-09) Sánchez Iza, Emma Cecilia; Santana Mayorga, Rita Cumandá
    Eotetranychus lewisi (Acari: Tetranychidae) is a phytophagous mite able to feed on a wide range of host plant species. Since this mite was recently reported in Ecuador, information on bioecological aspects of the pest is scarce. In this study, the morphological variability evaluated by Principal Component Analysis (PCA) and the genetic variation by genetic distance analysis using the ITS2 region were determined in populations of E. lewisi collected in blackberry plants from different localities from Tungurahua. In this study, blackberry leaves infested with E. lewisi populations were collected from different localities of Tungurahua, Cevallos (C), Quero (Q), Montalvo (M) and Pasa (P), all of these located at different altitude levels. In relation to the genetic study, it was observed that the percentages of the nitrogenous bases in the ITS2 fragment from the different localities show very little variable results. For Adenine, the values coincide with 29.72% for the populations of Cevallos, and 29.91% for Montalvo and Pasa, while the percentage of Cytosine is similar for the four localities (17.06%), likewise there were little variation for Guanine (18.17% for Cevallos; 18.35% for Quero; 18.72% for Montalvo and 18.90% in Pasa. Finally, the percentage of Thymine showed greater variation in Cevallos with 35.05 % with respect to the other populations of Quero (34.86%), Montalvo (34.31%) and Pasa (34.13%). In relation to the nitrogenous bases in the ITS2 fragment there is a greater presence of Thymine followed by Adenine, Guanine and finally Cytosine. On the other hand, the ACP showed that 93.14 and 94.67% of the morphometric variation of E. lewisi in blackberry plants from different locations was explained in 10 components. Of these, the variables that showed greater weight in the first two components were the length of the setae c1, c2, c3, d2, e2, f2 and h3, Sc1, d1, e1, f1 and f2 and in c Regarding the distances between setae, most of the variables were located in the first component (v2- v2, sc1-sc1, c3-c3, d1-d1, d2-d2, e2-e2, f1-f1, h2-h2 and h3-h3).