Yijuan Chen1, Guanghui Dai1. 1. Plant Health and Natural Products Lab, Key Lab of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Abstract
BACKGROUND: Tetranychus cinnabarinus (Boisduval) is one of the most important, highly polyphagous pests of a wide range of field and greenhouse crops throughout the world. The control of this mite is still based primarily on the use of synthetic chemical pesticides. In this study, we screened eight plant extracts from China and evaluated the natural compounds showing acaricidal properties from the plant extract, considering their potential use as an alternative to synthetic pesticides. RESULTS: In bioassay screening assays, the Cinnamomum camphora (L.) Presl extract showed significantly greater acaricidal activity against T. cinnabarinus than the other seven plant extracts tested. Five compounds were identified from the C. camphora extract via repeated column chromatography and gas chromatography-mass spectrometry analysis. All the compounds presented acaricidal activity, with 2,4-di-tert-butylphenol and ethyl oleate exhibiting the greatest activity. At 7 days after treatment in a potted seedling experiment, the LC50 values of 2,4-di-tert-butylphenol and ethyl oleate were found to be 1850.94 and 2481.65 mg kg(-1) respectively. Microscopic observations showed that the mites displayed the symptomology of poisoning. CONCLUSION: These results demonstrated that the C. camphora extract and its two active components show the potential to be developed as new natural acaricides for controlling carmine spider mites.
BACKGROUND:Tetranychus cinnabarinus (Boisduval) is one of the most important, highly polyphagous pests of a wide range of field and greenhouse crops throughout the world. The control of this mite is still based primarily on the use of synthetic chemical pesticides. In this study, we screened eight plant extracts from China and evaluated the natural compounds showing acaricidal properties from the plant extract, considering their potential use as an alternative to synthetic pesticides. RESULTS: In bioassay screening assays, the Cinnamomum camphora (L.) Presl extract showed significantly greater acaricidal activity against T. cinnabarinus than the other seven plant extracts tested. Five compounds were identified from the C. camphora extract via repeated column chromatography and gas chromatography-mass spectrometry analysis. All the compounds presented acaricidal activity, with 2,4-di-tert-butylphenol and ethyl oleate exhibiting the greatest activity. At 7 days after treatment in a potted seedling experiment, the LC50 values of 2,4-di-tert-butylphenol and ethyl oleate were found to be 1850.94 and 2481.65 mg kg(-1) respectively. Microscopic observations showed that the mites displayed the symptomology of poisoning. CONCLUSION: These results demonstrated that the C. camphora extract and its two active components show the potential to be developed as new natural acaricides for controlling carmine spider mites.