Toxicity of Essential Oils Against Red Flour Beetle, <i>Tribolium castaneum</i> (Herbst) (Coleoptera: Tenebrionidae)

Abstract

Contact and fumigant toxicity of the three essential oils, viz., cardamom (Elletaria cardamomum Maton), Cinnamon (Cinnamomum aromaticum Nees), and Clove (Syzygium aromaticum (L.) Merr. and Petry) were tested against the red flour beetle, Tribolium castaneum (Herbst) larvae and adults. Residual film bioassay was employed in Petri dish (5 cm dia.) for contact toxicity studies and 6cm × 1.8cm glass vials were used for testing fumigation actions. Three day old adults and 10- day old larvae were equally susceptible to the contact toxicity of cinnamon oil, with LD₅₀ values of 0.074 and 0.196 mg cm^-2 respectively. Cardamom oil provided higher toxicity to 14-day and 18- day old larvae having LD₅₀ value of 0.10mg cm^-2. In fumigation bioassay cinnamon oil provided the highest toxicity to adult and 10-, 14-, and 18-day old larvae, with LD₅₀ values of 0.03, 0.05, 0.088 and 0.09 mg cm^-3 respectively. Furthermore, 10-day old larvae were more tolerant than the adults to the contact toxicity of the essential oils, but 14- day old larvae had the same susceptibility as the adults. In contact and fumigation toxicity adults and all stages of larvae were more resistant to clove oil. Key words: Bioassay; cardamom; clove; toxicity; essential oil J. bio-sci. 14: 1-9, 2006