Toxicidade de óleos essenciais sobre Tyrophagus putrescentiae (Schrank) e Suidasia pontifica Oudemans (Acari : Astigmata)

Abstract

The use plant-derived essential oils are an alternative for mite control, such as the Tyrophagus putrescentiae (Schrank) and Suidasia pontifica Oudemans, in confined environment. The toxicity of essential oils from Cinnamomum zeylanicum, Eugenia uniflora, Eugenia uvalha, Melaleuca leucadendra, Piper marginatum and Schinus terebinthifolius was compared, through fumigation tests, to that from phosphine, product usually applied in warehouses. Mites were enclosed in screened small cages, allowing ventilation but not mites escaping. The cages were transferred to fumigation glass chambers with 2L capacity. The oils were applied in filter paper straps and fixed at the interior of the chambers. The glass chambers were closed and held in incubator chambers. Mite mortality was assessed after 48 hours of exposure. The mortality data were submitted to normality test and homocedasticity, and the means compared by the Tukey’s test at 5%. The oils from C. zeylanicum, S. terebinthifolius and E. uvalha were the most toxic. The CL50 and CL90 estimates were established for these oils and the eugenol through Probit analysis. The estimates indicated the eugenol as the most toxic treatment towards T. putrescentiae, LC50and LC90 equal to 0.23 μL/L and 14,51 μL/L of air, respectively. For S. pontifica, the LC50 estimate showed the eugenol as the most toxic treatment towards it with an LC50 estimate of 0.57μL/L of air. However, S. terebinthifolius was the most toxic treatment regarding the LC90 estimate, which was 23.48 μL/L of air.