title: Larvicidal activity against Plutella xylostella of cordycepin from the fruiting body of Cordyceps militaris.
abstract: The insecticidal activities of methanol extracts of Cordyceps militaris Link (Ascomycotina: Clavicipitaceae) cultured on fresh pupae of Bombyx mori L against 3rd-instar larvae of Plutella xylostella L were examined using direct contact application. The larvicidal activity was more pronounced in an extract of C militaris fruiting body than in an extract of the pupae separated from the culture. The biologically active constituent of the Cordyceps fruiting body was characterized as cordycepin (3'-deoxyadenosine) by spectroscopic analysis. Responses varied according to dose, exposure time and application method. In a leaf-dipping test, cordycepin at 500 mg litre-1 caused no mortality at 1 DAT (day after treatment) but 78 and 100% mortality at 2 and 4 DAT, respectively, whereas 34 and 88% mortality at 3 and 5 DAT, respectively was observed at 300 mg litre-1. Cordycepin caused body colour change from pale green to dark brown and eventually body lysis. These results suggested that the larvicidal action may be attributable to a direct effect rather than an inhibitory action on chitin synthesis. There was a significant difference in insecticidal activity of cordycepin between leaf dipping (500 mg litre-1) with 100% mortality and topical application (10 micrograms per larva) with 0% mortality, suggesting that cordycepin has stomach action. Cordycepin merits further study as a potential P xylostella control agent or as a lead compound.
authors.affiliation: School of Agricultural Biotechnology, Research Center for New Bio-Materials in Agriculture, Seoul National University, Suwon 441-744, Republic of Korea.
authors.forename: Jun-Ran
authors.initials: JR
authors.lastname: Kim
authors.forename: Sung-Hum
authors.initials: SH
authors.lastname: Yeon
authors.forename: Ho-San
authors.initials: HS
authors.lastname: Kim
authors.forename: Young-Joon
authors.initials: YJ
authors.lastname: Ahn
mesh_terms: D000818:Animals; D032661:Cordyceps / Q000737:chemistry*; D003839:Deoxyadenosines / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects*; D015394:Molecular Structure; D009036:Moths / Q000187:drug effects* / Q000254:growth & development; D010944:Plants; D013997:Time Factors
chemical_list: D003839:Deoxyadenosines; D007306:Insecticides; C058120:cordycepin