Population study of the aedes aegypti mosquito and measures of intervention in the field with use of essential oil of croton rhamnifolioides with deterrent effect

Abstract

The control of the mosquito from larvicides has been the most used form in the prevention of diseases, however, populations of Aedes spp. have become resistant to these compounds, requiring more efficient and less aggressive forms of control to the environment. The objective of this work was to carry out a mosquito population study and to test the efficiency in Croton rhamnifolioides essential oil field as an oviposition deterrent in 30 traps installed in the Várzea-Recife cemetery. The traps were randomly divided into two groups, using 15 test traps containing essential oil and another 15 for control. The essential oil was obtained by hydrodistillation with a content varying from 0.58% to 1.4% (w/w) and its chemical constituents identified by gas chromatography coupled with mass spectrometry, presenting 1,8-cineol (16.57% ) and (E) -Caryophyllene (11.32%) as major constituents. The test of deterrence was repeated 25 times over a period of 12 months. The oil was used at a concentration of 100 μg · mL-1. The detergency response to oviposition was evaluated by counting and comparing the number of eggs placed in each set of traps. As results, 110,157 eggs were collected, presenting an infestation index of 99.8%. Of the 2,964 larvae analyzed, 96% were A. aegypti and only 4% A. albopictus. The oviposition delayed effect was observed in 17 (68%) of the 25 analyzed cycles, with ovitraps with oil showing a quantity of eggs 39% smaller than the number found in the control ovitrampas. The T-student test showed significant difference between test and control ovitrampas (p <0.002). It was concluded that the Várzea cemetery had a high rate of infestation of Aedes spp. and that the essential oil emulsion tested had deterrent power, despite the adverse conditions encountered in the field and the volatility of essential oil. It is recommended, however, additional studies aiming at enhancing its deterrent oviposition power in the field.