Chemical composition and larvicidal activity of the essential oils from Minthostachys spicata (Benth) Epling and Clinopodium bolivianum (Benth) Kuntze against Premnotrypes latithorax Pierce

Abstract

The larvicidal activity of leaf essential oils (EOs) from Minthostachys spicata (Benth) Epling and Clinopodium bolivianum (Benth) Kuntze against Premnotrypes latithorax Pierce was evaluated. EOs were analyzed by GC-FID and GC-MS. Major compounds in M. spicate EO were pulegone, isomenthone, and menthone, while in C. bolivianum EO were isomenthone, thymol, and menthone. Different concentrations of the EOs were dissolved in aqueous solution containing 2% of Tween 80, and 1 mL of each concentration was impregnated on 10 cm-diameter disk of filter paper previously introduced into separate polyethylene containers. The larval mortality was observed for 24 h of post exposure. Both EOs exhibited significant larvicidal activity, with LC50 and LC90of 0.040 and 0.095 µL/cm2 for M. spicata and 0.088 and 0.248 µL/cm2for C. bolivianum, respectively. Both leaf EOs, but particularly M. spicate EO, may be considered as potent source to produce natural larvicides against P. latithorax.