Fumigant toxicity of three essential oils on the eggs of Acanthoscelides obtectus (Say) (Coleoptera:Bruchidae)

Fumigant toxicity of the essential oils from Lavandula hybrida, Rosmarinus officinalis and Eucalyptus globulus against the eggs of Acanthoscelides obtectus was assessed. The essential oil vapours were toxic to eggs with LC50 values ranging between 1.3 and 35.1 mul/l air, depending on egg age and the essential oil. In all cases, the young eggs (less than or equal to 3-day old) were more tolerant to essential oil vapours than the older ones (greater than or equal to 4-day old). Apart from the inhibition of hatching, the exposure of eggs to essential oil vapours increased the subsequent mortality of hatched larvae. The influence of length of exposure to essential oil vapours on egg hatchability was also significant. (C) 2003 Elsevier Ltd. All rights reserved.