title: Toxicity and sublethal effects of methoxyfenozide on Spodoptera exigua (Lepidoptera: Noctuidae).
abstract: The toxicity and sublethal effects of methoxyfenozide were evaluated in third instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), that fed on contaminated semisynthetic diet. The LC50 value was estimated at 0.23 mg of active ingredient (AI) /kg diet (range, 95% CI: 0.17-0.37) at 264 h after treatment. The effects on development, survival, and reproduction were observed in third instars of this pest that survived exposure to an LC25 concentration of methoxyfenozide. The larvae from the insecticide treatment exhibited lower pupal weights, an increase in both larval and pupal developmental times and a higher frequency of malformations of the wings in adults than untreated larvae. Adults from the methoxyfenozide treatment did not show reduced fecundity (mean cumulative number of eggs laid per female), but fertility as measured by the percentage of eggs hatched (fertility) was significantly reduced compared with untreated control insects. No significant effects were observed on pupal sex ratio. We concluded that the lethal and sublethal effects of methoxyfenozide are likely to have a significant impact on S. exigua populations on treated crops.
authors.affiliation: Instituto de Investigaciones Agropecuarias y Forestales, Universidad, Michoacana de San Nicolás de Hidalgo, 58880 Tarímbaro, Michoacín, Mexico.
authors.forename: Christian-Luis
authors.initials: CL
authors.lastname: Rodríguez Enríquez
authors.forename: Samuel
authors.initials: S
authors.lastname: Pineda
authors.forename: José I
authors.initials: JI
authors.lastname: Figueroa
authors.forename: Marcela-Inés
authors.initials: MI
authors.lastname: Schneider
authors.forename: Ana-Mabel
authors.initials: AM
authors.lastname: Martínez
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility; D006834:Hydrazines / Q000633:toxicity*; D007300:Insect Control; D007605:Juvenile Hormones / Q000633:toxicity*; D007814:Larva; D009036:Moths; D052287:Oviparity; D011679:Pupa; D036401:Toxicity Tests, Chronic
chemical_list: D006834:Hydrazines; D007605:Juvenile Hormones; C406712:methoxyfenozide