title: Development and evaluation of granule and emulsifiable concentrate formulations containing Derris elliptica extract for crop pest control.
abstract: Derris elliptica Benth. extracts containing rotenone have long been used as natural insecticides, but time-consuming preparation processes and the short shelf life of the extract limit their use in pest control. In this study, stable water-dispersible granules and emulsifiable concentrate liquids containing Derris extract (equivalent to 5% w/w of rotenone) were developed with simple techniques. Accelerated degradation kinetics of rotenone in the Derris extract, and in both formulations, indicated that its degradation followed first-order kinetics. The predicted half-life (t(1/2)) and shelf life (t(90%)) at 30 degrees C of rotenone in Derris extract were 520 and 79 days, respectively. Derris granules and emulsifiable concentrate clearly prolong the stability of rotenone 8-fold (t(90%) = 633 days) and 1.4-fold (t(90%) = 110 days), respectively. The study of rotenone degradation after application onto plants indicated that both formulations would be effective for up to 3 days after spraying. Preliminary efficacy testing indicated that the Derris emulsifiable concentrate was clearly more effective than Derris water-dispersible granules in controlling Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae).
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. wruedeek@pharmacy.psu.ac.th
authors.forename: Ruedeekorn
authors.initials: R
authors.lastname: Wiwattanapatapee
authors.forename: Attawadee
authors.initials: A
authors.lastname: Sae-Yun
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Petcharat
authors.forename: Chitchamai
authors.initials: C
authors.lastname: Ovatlarnporn
authors.forename: Arunporn
authors.initials: A
authors.lastname: Itharat
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D018556:Crops, Agricultural / Q000469:parasitology*; D029866:Derris / Q000737:chemistry*; D004304:Dosage Forms; D004655:Emulsions / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry* / Q000494:pharmacology; D007700:Kinetics; D010571:Pest Control; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D010935:Plant Diseases / Q000469:parasitology; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D012402:Rotenone / Q000737:chemistry / Q000494:pharmacology; D018411:Spodoptera / Q000187:drug effects
chemical_list: D004304:Dosage Forms; D004655:Emulsions; D007306:Insecticides; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D012402:Rotenone