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 Cinnamomum 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 The LC50 value of C. cassia and C. zeylanicum oils was 37.66 and 72.62 mg L–1, respectively, in leaf‐dipping bioassays against Ricania sp. nymphs, and 77.38 and 134.86 mg L–1 in 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. When examined by gas chromatography mass spectrometry, the cinnamaldehyde content of C. cassia and C. zeylanicum oils was 80.20% and 46.32%, respectively. Based on the 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–1) demonstrated the most potent insecticidal activity, followed by 4‐hydroxy‐3‐methoxycinnamaldehyde (172.19 and 212.77 mg L–1) and hydrocinnamaldehyde (275.05 and 318.63 mg L–1). CONCLUSION The findings revealed that C. cassia oil, C. zeylanicum oil and cinnamaldehyde have potential value in the management of Ricania sp. and could be valuable as effective insecticides. © 2017 Society of Chemical Industry