Produtos biológicos e naturais à base de plantas sobre carrapatos Rhipicephalus (Boophilus) microplus (Canestrini 1887)

Abstract

The Rhipicephalus (Boophilus) microplus tick is an ectoparasite mite of interest in animal health, as it is involved in the transmission of important diseases caused by protozoa, viruses and rickettsia, as well as in the production of direct damages due to blood spillage, allergy production and injury Cutaneous. Control measures less aggressive to animals and the environment and that can control said ectoparasite are necessary. Biological control through entomopathogenic fungi and the use of herbal products such as commercial products and essential oils may be viable strategies for the control of R. (B). Microplus in different phases of life. In this sense, the objective of this work was to evaluate the effect of entomopathogenic fungi, alternative commercial products based on plants and essential oils on eggs and larvae of R. (B). Microplus. To obtain the eggs, the engorged females were collected from animals free of the application of carrapaticides and identified through the morphological characteristics of the species. The commercial fungi used were Metarhizium anisopliae and Beauveria bassiana, at the concentration of 1 x 108 conidia mL-1 per gram. The commercial products used were Azamax[marca registrada], Base Nim[marca registrada], respectively at concentrations 12g / L (1.2% w / w), 0.12% w / w and Pyretro 11g / L (1.25g pure pyrethrin). Concentrations recommended for other pests and mites of agronomic interest. The essential oil of pitanga, Eugenia uniflora, was evaluated at concentrations: 0; 0.31; 0.62; 1.25; 2.5; 5; 10%. For the experiments with eggs, these were immersed in the suspensions of the evaluated products, using eight repetitions with 30 eggs in each repetition. For larvae the products were pulverized using eight replicates with 20 larvae each. In both experiments, sterilized mineral water was used as the control. After application of the treatments, the bioassays were conditioned in an air-conditioned room at a temperature of 28 ± 2ºC, relative humidity of 65 ± 10%. For the bioassays with eggs the percentage of hatching of the larvae was evaluated after 30 days of application of the products. For larvae the evaluation was daily, during 21 days, quantifying the number of individuals killed. In the evaluations on eggs, it was verified that M. anisopliae and B. bassiana reduced the hatching percentage, with respectively 2.5% and 4.58%, differing significantly from the control (85.41%). Likewise, the percentage of hatching in the treatments with alternative commercial products Azamax[marca registrada] (54,16), Base Nim[marca registrada] (40,83%) and Piretro (69,16%) was reduced, differing significantly from the control (92, 91%). With respect to E.uniflora essential oil, concentrations of 0.62% and 5% significantly reduced the hatching percentage in relation to the control, to 18.11% and 38.75%, respectively. Regarding larvae, the percentages of mortality caused by M. anisopliae and B. bassiana were 91.87% and 84.37%, differing significantly from Witness (53.12%), respectively. The percentages of mortality caused by the alternative products Azamax[marca registrada] (73.12%), Base Nim[marca registrada] (83.75%) and Piretro (66.25%) differed significantly from the control group (10.00%). And for the different concentrations of E. uniflora (0.62%), (1.25%), (2.5%), (5%) and (10,00%), the percentages of larval mortality were respectively 46.87%, 63.75%, 85.00%, 96.25% and 91.25%, differing significantly from the control (16.37%). Considering the above, the control agents evaluated have potential as an alternative to control R. (B). microplus, both in the egg phase and in the larval stage. However, there is a need for further studies to evaluate the effects of these control agents under field conditions.