Efeitos de óleos essenciais no controle de Tetranychus urticae Koch (Acari: tetranychidae) e Lipaphis pseudobrassicae (Davis) (Hemiptera: Aphididae) e seletividade aos inimigos naturais

Abstract

The research aimed to determine the acaricidal potential of essential oils on Tetranychus urticae Koch and Neoseiulus californicus Koppert; to investigate the effect on T. urticae eggs; to evaluate the toxicity of oils on Lipaphis pseudobrassicae and Aphidius sp; evaluate the repellent effect and the instantaneous rate of growth. Tested oils: Citrus aurantifolia L., Citrus limon (L.) Burm. f., Citrus sinensis (L.) Osbeck., Lippia sidoides Cham., , Croton rhamnifolioides Pax & Hoffm. , Piper divaricatum G. Mayer, Croton grewioides Baill., positive control (Azamax) and control (water + 0.5% DMSO). All oils were toxic to T. urticae, with L. sidoides, P. divaricatum, C. sinensis, and C. limon the ones that presented better LC50. L. sidoides (5.26 μL/mL) and P. divaricatum (6.66 μL/mL) showed higher toxicity to T. urticae eggs. C. grewioides (163.30 μl/mL) and C. sinensis (143.54 μL/mL) provided lower mortality for N. californicus. For L. pseudobrassicae, C. grewioides (2.78 μL/20 mL) and C. rhamnifolioides (3.70 μL/20 mL) were more toxic (LC50). The oils were repellent at the highest concentrations in 24 and 48 hours, exeto C. sinensis. All oils reduced the instantaneous rate of growth, with P. divaricatum (150 μl/20 ml), C. limon (120 μL/20 ml) and Azamax (500 μL/20 ml) the smallest. P. divaricatum, C. limon and C. rhamnifolioides were the ones that reduced the number of nymphs, with 96.7%, 96.5% and 96.2%, respectively. For Aphidus sp in the development stage (mummy), the highest LC50s were 147.67 mL/20mL (L. sidoides); 51.34 mL/20mL (C. aurantifolia); 49.43 mL/20mL (C. rhamnifolioides); 41.66 mL/20 mL (C. sinensis) and 41.41 mL/20 mL (P. divaricatum). In the adult phase of Aphidus sp the LC50 were higher when compared to L. pseudobrassicae, ranging from 0.28 mL/mL (Croton grewioides) to 2.37 mL/mL (C. sinensis), with C. grewioides being 8.37 times more toxic to the parasitoid.