Lethal and sublethal effects of methoxyfenozide and spinosad on Spodoptera littoralis (Lepidoptera: Noctuidae).
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.
Pineda
Samuel
S
Protección de Cultivos, Escuela Técnica Superior de Ingenieros Agrónomos, E-28040 Madrid, Spain. spineda_us@yahoo.com
Schneider
Marcela-Inés
MI
Smagghe
Guy
G
Martínez
Ana-Mabel
AM
Del Estal
Pedro
P
Viñuela
Elisa
E
Valle
Javier
J
Budia
Flor
F
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
D004338:Drug Combinations; D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; D018942:Macrolides; D010573:Pesticide Residues; C406712:methoxyfenozide; C415329:spinosad