|Selin-rani, Selvaraj - Manonmaniam Sundaranar University (MSU)|
|Senthil-nathan, Sengottayan - Manonmaniam Sundaranar University (MSU)|
|Thanigaivel, Annamalai - Manonmaniam Sundaranar University (MSU)|
|Vasantha-srinivasan, Prabhakaran - Manonmaniam Sundaranar University (MSU)|
|Edwin, Edward-sam - Manonmaniam Sundaranar University (MSU)|
|Ponsankar, Athirstam - Manonmaniam Sundaranar University (MSU)|
|Lija-escaline, J. - Manonmaniam Sundaranar University (MSU)|
|Kalaivani, Kandaswamy - Sri Jayachamarajendra College Of Engineering|
|Abdel-megeed, Ahmed - Alexandria University Of Egypt|
|Alessandro, Rocco - Former ARS Employee|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2016
Publication Date: 9/30/2016
Citation: Selin-Rani, S., Senthil-Nathan, S., Thanigaivel, A., Vasantha-Srinivasan, P., Edwin, E., Ponsankar, A., Lija-Escaline, J., Kalaivani, K., Abdel-Megeed, A., Hunter, W.B., Alessandro, R.R. 2016. Toxicity and physiological effect of quercetin on generalist herbivore, Spodoptera litura Fab. and a non-target earthworm Eisenia fetida Savigny. Chemosphere. 165:257-267.
Interpretive Summary: Novel chemistries associated with botanical insecticides may provide alternatives to conventional insecticides for a wide range of insect pets from psyllids to caterpillar pests like the Oriental leafworm. Many botanical chemistries are biodegradable and have lower mammalian toxicity than conventional insecticides. A novel flavonoid, quercetin, was isolated from a medicinal plant. Toxicity to larvae of the Oriental leafworm was assessed across a range of extract concentrations. Results demonstrated that 6 ppm of quercetin caused 94.6% mortality of first, 91.8% of second, 88% of third, and 85.2% of fourth instars respectively. Quercetin was less toxic to earthworms than two conventional insecticides. Quercetin may bean ecofriendly alternative to conventional insecticides, pending validation under field conditions.
Technical Abstract: A novel flavonoid, quercetin, was isolated from Euphorbia hirta L., a medicinal plant using chromatography techniques including: Thin-layer chromatography, Column chromatography, Nuclear magnetic resonance spectroscopy. Toxicity to larval of Spodoptera litura analyze pupal weight, survival rate, fecundity, egg hatchability, population growth index, nutritional index and histopathology of treated larvae at a range of extract concentrations. Results demonstrated that 6 parts-per-million, ppm, of quercetin caused 94.6% mortality of first, 91.8% of second, 88% of third, and 85.2% of fourth instars respectively. The lethal concentrations (LC50 and LC90) were calculated as 10.88 and 69.91 ppm for fourth instars. The changes in consumption ratio and approximate digestibility produced a reduction in growth rates. Histopathology examinations revealed that the cell organelles were severely damaged post exposure by feeding. Analyses of earthworm toxicity effects resulted in significantly lower rates compared to commercial synthetic insecticides (chloropyrifos and cypermethrin). These results suggest that the botanical compound (quercetin), may provide a new biorational product as an ecofriendly alternative. Validation of the potential of quercetin, still needs to be demonstrated under field conditions, and across other insects, where formulation will be important in maintaining activity.