Avaliação do extrato de folhas do cinamomo (Melia azedarach L.) sobre a mortalidade e reprodução do carrapato Amblyomma sculptum (Berlese, 1888).

Abstract

Problems related to tick-borne pathogens remain a constant concern, as currently evidenced by the outbreak of Brazilian spotted fever, caused by the bacterium Rickettsia rickettsii and transmitted by the vector Amblyomma sculptum (Berlese, 1888) (Acari: Ixodidae). The indiscriminate use of chemical products, with uncontrolled dosages and disregard for withdrawal periods, has led to the development of resistance in ticks, in addition to posing risks to human and animal health and the environment. An alternative to chemical acaricides is the use of plant extracts. Therefore, the objective of the present study was to produce a hydroalcoholic extract from the leaves of Chinaberry (Melia azedarach L.) to evaluate its effects on the mortality and reproduction of engorged females of A. sculptum. Two preliminary trials were conducted at the Parasitology Laboratory of the Center for Agricultural Sciences of the Federal Institute of Education, Science and Technology of Minas Gerais (IFMG) – Bambuí Campus, in order to select the best methodology for the final experiment.in which the teleogynes were immersed in 30 ml, of the hydroalcoholic solution for during the times 2 and 5 minutes at different concentrations. Based on the preliminary results, a new experiment was carried out with 5-minute immersion. Due to the difficulty in obtaining sufficient tick specimens and the need for further replicates the concentrations of 0,05 g/ml, 0,1 g/ml, and 0,2 g/ml were excluded from the final experiment because of their low efficacy in tick control. The final experiment employed concentrations of 0,4 g/ml, 0,6 g/ml and 0,7 g/ml of the hydroalcoholic extract of M. azedarach. An additional experiment was also performed using the spraying method, in which 30 mL of the extract was applied to engorged females of A. sculptum. According to the results of both immersion and spraying assays, the leaf extracts of M. azedarach were effective in controlling the ectoparasite A. sculptum. It can be concluded that increasing the extract concentration enhances its efficacy in tick control.