Comparison of durability of Mentha longifolia (Lamiaceae) essential oil and its nanoemulsion against Ephestia kuehniella (Lep.: Pyralidae)

In this study, the nanoemulsion containing Mentha longifolia essential oil was produced by using high-pressure homogenization method and its fumigant toxicity was compared with ordinary M. longifolia essential oil on different stages of Ephestia kuehniella. Experimental conditions were as follows; 27±1 °C, 70± 5% relative humidity in total darkness. Concentrations of 111.1-1111.1 and 62.9-92.6 µl/l air of oil have been used to control larva and eggs, respectively. Nanoemulsion concentrations were studied at 122.2-1111.1 µl/l air for larvicide experiment and 81.4-114.8 µl/l air for ovicidal stage. PT50 value at 1111.1 µl/l air as a larvicide for nanoemulsion and oil was estimated about 15.18 and 3.69 days, respectively. This value, at 92.6 µl/l air on egg was 14.44 and 2.58 days, respectively. The relative median potency parameter (RMP) showed that there was significant difference between PT50 values of essential oil and its nanoemulsion on both of the two stages of pest. Results showed that nanoemulsion containing M. longifolia oil can release slow properties lead to durability of fumigant toxicity of oil in the long term. Therefore, this new formulation could be considered as a new and ecofriendly biopesticide in pest control.