title: Lethal and sublethal effects of methoxyfenozide and spinosad on Spodoptera littoralis (Lepidoptera: Noctuidae).
abstract: Susceptibility to methoxyfenozide of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) larvae was determined through exposure of neonate and fourth instars to dipped and sprayed pepper, Capsicum annum L., leaves. Methoxyfenozide and spinosad were tested against adults of this noctuid by oral, residual, and topical application. In larvae, we evaluated five (range, 0.001-10 mg active ingredient [AI] /liter) and six (range, 1-250 mg [AI] /liter) concentration levels by instars, respectively, by using two application methods at three different age leaf residues (0, 3, and 6 d after application). According to LC50 values, no significant differences were observed between the same age leaf residues of both application methods at 96 and 72 h after ingestion treatment on neonates and fourth instars, respectively. Nevertheless, toxicity of methoxyfenozide decreased significantly after time. For both application methods, the LC50 values of the first leaf residue (0 d after application) were significantly lower than those of 6-d-old residues. Furthermore, larval weight of fourth instars fed for 48 h with pepper, Capsicum annum L., leaves containing methoxyfenozide was significantly suppressed. Spinosad and methoxyfenozide reduced in a dose-dependent manner the fecundity and fertility of S. littoralis adults when treated oral and residually. Likewise, when methoxyfenozide was administered orally in three different adult crosses, the fecundity was strongly affected, independently of the treated sex. We conclude that the combination of lethal and sublethal effects of methoxy-fenozide and spinosad might exhibit significant effects on the population dynamics of S. littolaris.
authors.affiliation: Protección de Cultivos, Escuela Técnica Superior de Ingenieros Agrónomos, E-28040 Madrid, Spain. spineda_us@yahoo.com
authors.forename: Samuel
authors.initials: S
authors.lastname: Pineda
authors.forename: Marcela-Inés
authors.initials: MI
authors.lastname: Schneider
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.forename: Ana-Mabel
authors.initials: AM
authors.lastname: Martínez
authors.forename: Pedro
authors.initials: P
authors.lastname: Del Estal
authors.forename: Elisa
authors.initials: E
authors.lastname: Viñuela
authors.forename: Javier
authors.initials: J
authors.lastname: Valle
authors.forename: Flor
authors.initials: F
authors.lastname: Budia
mesh_terms: D000818:Animals; D002212:Capsicum; D004338:Drug Combinations; D005260:Female; D005298:Fertility / Q000187:drug effects; D006834:Hydrazines / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000494:pharmacology*; D007814:Larva / Q000254:growth & development / Q000502:physiology; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D010573:Pesticide Residues; D011157:Population Dynamics; D018411:Spodoptera / Q000254:growth & development / Q000502:physiology*; D018675:Toxicity Tests
chemical_list: D004338:Drug Combinations; D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; D018942:Macrolides; D010573:Pesticide Residues; C406712:methoxyfenozide; C415329:spinosad