Insecticidal activities of their components derived from the essential oils of Cinnamomum sp. barks and against Ricania sp. (Homoptera: Ricaniidae), a newly recorded pest

BACKGROUND Insecticidal activities of Cinnamomum cassia and C. zeylanicum oils and their components are not known against Ricania sp. Insecticidal activities of major components derived from C. cassia and C. zeylanicum oils were examined in spray and leaf dipping bioassays against Ricania sp. nymphs and adults. RESULTS LC50 value of C. cassia and C. zeylanicum oils was 37.66 and 72.62 mg/L, respectively, in the leaf dipping bioassays against Ricania sp. nymphs, and 77.38 and 134.86 mg/L in the spray bioassays against Ricania sp. adults. The insecticidal activity of C. cassia oil was 1.74-1.93 times greater than that of C. zeylanicum oil. In the components of C. cassia and C. zeylanicum oils examined by GC-MS, the content of cinnamaldehyde derived from C. cassia and C. zeylanicum oils was 80.20% and 46.32%, respectively. Based on LC50 values of cinnamaldehyde, hydrocinnamaldehyde and 4-hydroxy-3-methoxycinnamaldehyde against Ricania sp. nymphs and adults, cinnamaldehyde (LC50, 31.25 and 62.43 mg/L) demonstrated the most potent insecticidal activities, followed by 4-hydroxy-3-methoxycinnamaldehyde (172.19 and 212.77 mg/L) and hydrocinnamaldehyde (275.05 and 318.63 mg/L). CONCLUSION The findings revealed that C. cassia oil, C. zeylanicum oil and cinnamaldehyde have potential value in management of Ricania sp. and could be valuable as effective insecticides.