Avaliação in vitro da atividade pesticida de Piper tuberculatum Jacq. (Piperaceae) para o controle das infestações de Rhipicephalus microplus (Ixodideae) e Haematobia irritans (Muscidae)

Abstract

R. microplus and H. irritans are ectoparasites that cause economic losses in Brazilian livestock. Natural products extracted from plants are promising sources for pest control, reducing the negative effects caused by the uncontrolled application of commercially available acaricides. P. tuberculatum stands out in the surveys due to its insecticidal actions. Therefore, the objective of this work is to perform the phytochemical study of P. tuberculatum, as well as its insecticidal potential against H. irritans and R. microplus. In this study the insecticidal potential of extracts and isolated substances of P. tuberculatum was evaluated, extracts were obtained from leaves, fruits and stalks prepared with solvents: hexane, chloroform, ethyl acetate and ethanol in six concentrations, however, for Como Concentrations. The activity of the extracts was evaluated on engorged larvae and females of R. microplus and adults H. irritans. The isolated and identified substances were piplatin, pelitorin and 3,4,5-trimethoxy dihydrocinnamic acid isolated from ethanolic extract of P. tuberculatum fruits. There is no immersion test of adults of R. microplus, it was observed that it offers effective results of fruit extract with 99,7%, and for other extracts or fruit are also shown as promising for adult immersion test. For R. microplus larvae a 24 hour evaluation, observing LC50 of 1,23 mg/mL and 1,29 mg/mL for hexenic leaf and bead extracts, respectively. The LC50 found for H. irritans on impregnated filter paper, the ethanolic extract of stems at LC50 was 6,00 mg/mL, which was the best result for this test. However as isolated substances, the message shown (LC50 of 0,48 mg/mL), this may have been due to a combination of compounds, since in the extracts with a combination of compounds, with the most known results. Thus, the present work demonstrates that the species P. tuberculatum presents an important acaricidal action.