Potencial acaricida de óleos essenciais de espécies do gênero Piper sobre o ácaro rajado Tetranychus urticae Koch (Acari : Tetranychidae)

Abstract

Tetranychus urticae (two-spotted spider mite) is a cosmopolitan species, which may attack crops like tomatoes, beans, papaya, and ornamentals. In Brazil, this pest has been recorded in several states. In Pernambuco, their first record was in 1985, after the beginning of irrigated crops in the municipality of Petrolina. The best way to control this pest is the use of conventional acaricides. Aiming new control practices with lower mammalian toxicity and low persistence in soil, essential oils have been widely investigated as alternatives to these acaricides. This study aims to identify the chemical constituents and evaluate potential acaricide, through lethal and sublethal effects of essential oils from leaves of Piper aduncum, P. arboreum, P. caldense and P. tuberculatum on the mite. Analysis by GC/MS revealed the presence of dillapiol (46.7%), bicyclogermacrene (17.3%), γ-Muurolene (9.6%) and 2-epi-β-Funebrene (10.6%) as the main components in the oils of P. aduncum, P. arboreum, P. caldense and P. tuberculatum, respectively. All oils were toxic and were involved in the behavior of the mite. In the fumigation, the positive control, eugenol was the most toxic and the strongest influence on oviposition. Among the oils tested, the mite was more susceptible to the oils of P. aduncum (LC50 = 0.01 μL/L air) and P. tuberculatum (LC50 = 0.50 μL/L air). The lowest concentration of the oils, which promoted a significant reduction in the number of eggs was 3x10-3 μL /L air for P. aduncum. There was no significant difference among the tested oils and eugenol in contact bioassays. The oils of P. tuberculatum and P. caldense were 25.5 and 5.0 times more repellent than eugenol, respectively. These data suggest that these oils have potential acaricide for T. urticae control.