Antifeedant and insecticidal activity of Clerodendron infortunatum Gaertn. (Verbinaceae) extract on tea mosquito bug, Helopeltis theivora Waterhouse (Hetoraptera : Miridae)

作者：Roy Somnath^*; Mukhopadhyay Ananda; Gurusubramanian G

来源：Research on Crops, 2009, 10(1): 152-158.

• Antifeedant
• antiovipositional
• Clerodendron infortunatum
• Helopeltis theivora
• theivora
• insecticide
• ovicide

Antifeedant and insecticidal activities of Clerodendron infortunatum Gaertn., a common weed, were investigated on eggs, nymphs and adults of tea mosquito bug (TMB), Helopeltis theivora Waterhouse. Different solvent extracts (water, methanol, acetone and petroleum ether) of C. infortunatum at different concentrations (1, 2, 4 and 8%) were used. These solvent extracts of exhibited mortality of IT theivora in the tune of 20-60% in water, 37-77% in petroleum ether, 40-80% in acetone, and the highest mortality 70-97% in methanol extract. Depending on LC(50) values the relative toxicity was found to be in order of methanol extracts > petroleum-ether extracts > acetone extracts > water extracts. Significant egg mortality and prolonged incubation period were observed in H. theivora. eggs when sprayed with different concentrations of solvent extracts (except water) on freshly laid eggs of H. theivora over control. Higher concentrations (4 and 8%) of C. infortunatum showed higher rate of egg mortality than lower concentrations (I and 2%). Methanol, acetone and petroleum ether extracts of C. infortunatum caused more or less same egg mortality under laboratory conditions. Further, the extracts of C. infortunatum found to be effective in prolongation of incubation and killing the neonate nymphs of hatched H. theivora that successfully hatched from the treated eggs. High antifeedant activity was noticed in all the concentrations of different solvent extracts and feeding spots of H. theivora in tea foliage were reduced in the tune of 38.13-87.24% over untreated control. Petroleum ether extract exhibited highest antifeedant property by deterring H. theivora than the other three solvents. In field condition both lower and higher concentrations of different solvent extracts of C. infortunatum registered a significant per cent reduction of feeding punctures when compared with untreated check. No phytotoxic effect was observed in field. Made tea samples were taint free. Organoleptic test revealed leaf, infusions and liquor strength as good, scoring 6.5-7.0 on a 10-point scale. Availability and distribution of this weed (C. infortunatum) in and around tea growing areas of sub-Himalayan Terai and the Dooars, alongwith its processing for economic utility have been described. In the light of above findings, the feasibility of its inclusion in the current IPM programme of tea has also been discussed.

• 出版日期2009-4