Acaricidal and insecticidal responses of Cinnamomum cassia oils and main constituents

Insecticidal and acaricidal responses of Cinnamomum cassia oils made by organic solvent (OS), steam distillation (SD), and supercritical fluid (SF) and their components were examined in two bioassays (contact and fumigant bioassays) against Plodia interpunctella , Sitophilus oryzae , S. zeamais , Tyrophagus putrescentiae , and Sitotroga cerealella adults. Using the contact or fumigant bioassay against T. putrescentiae adults, OS oil exhibited the strongest toxicities (50% lethal dose [LD 50 ], 2.60 μg/cm 2 and 1.34 μg/cm 3 ), followed by SF and SD oils. Furthermore, using two bioassays, SD oil against S. oryzae and S. zeamais adults exhibited the strongest toxicities (LD 50 , 102.25 μg/cm 2 and 68.62 μg/cm 3 , 102.03 μg/cm 2 and 57.59 μg/cm 3 ), followed by SF and OS oils. Using the fumigant bioassay against S. cerealella and P. interpunctella adults, OS oil exhibited the strongest toxicities (LD 50 , 1.17 μg/cm 3 and 0.79 μg/cm 3 ) followed by SF and SD oils. Cinnamaldehyde, cinnamyl acetate, and coumarin against T. putrescentiae adults showed no significant differences in the contact bioassay, but in the fumigant bioassay, cinnamaldehyde exhibited the highest toxicity (LD 50 , 0.91 μg/cm 3 ) followed by cinnamyl acetate and coumarin. Against S. oryzae , S. zeamais , S. cerealella, and P. interpunctella adults, cinnamaldehyde using two bioassays exhibited the most potent toxicities (LD 50 , 108.81 μg/cm 2 and 77.80 μg/cm 3 , 104.72 μg/cm 2 and 36.48 μg/cm 3 , 0.57 μg/cm 2 and 2.29 μg/cm 3 ), followed by coumarin and cinnamyl acetate in order. The results showed that cinnamaldehyde and the C. cassia oils could be effective values in the management of stored product pests.