The Insecticidal and Repellent Activity of Soil Containing Cinnamon Leaf debris against Red Imported Fire Ant Workers

In the study, the amount of cinnamaldehyde and eugenol in soil containing cinnamon leaf debris were determined at different depths by high performance liquid chromatography (HPLC). The insecticidal activity and repellence of the soil was tested separately. Results showed that higher contents of cinnamic aldehyde and eugenol were found in soil at depths of 5 - 10 cm. In the insecticidal toxicity bioassay, the corrected mortality of major workers treated with cinnamon soil at depths of 5 - 10 cm, which was higher than the other soil depths, increased from 13.3% to 80.0% with contact time from 1 - 5 d. Likewise, the corrected mortality of minor workers also increased from 6.7% to 100.0%. In the repellent activity bioassay, the repellency (96.3%) of major and minor workers treated with cinnamon soil at depths of 5 - 10 cm for 24 h were significantly higher than the other treatments. This result revealed ecological value of cinnamon. Soil underneath cinnamon contained cinnamaldehyde and eugenol from fallen leaves, and these components showed insecticidal activity and repellence against red imported fire ants. Perhaps we could control the red imported fire ants by planting cinnamon in some possible regions or by incorporating cinnamon leaves into soil where cinnamon will not grow