The effects of spiromesifen on life history traits and population growth of two-spotted spider mite (Acari: Tetranychidae).
Laboratory bioassays were conducted to evaluate the effects of spiromesifen on gross fecundity, gross fertility, net fertility and population growth of two-spotted spider mite (Tetranychus urticae Koch) after treatments with four acaricide concentrations: 180 mg/l, i.e. maximum recommended concentration for use in glasshouses against spider mites, 18, 1.8, and 0.18 mg/l, i.e. concentration discriminative for eggs and immatures in preliminary studies which produced 100% mortality of these stages. Quiescent female deutonymphs were treated in the first assay, and young pre-ovipositing females in the second and third, in which exposure lasted 6 h and 20 h, respectively. In the first assay, the 180, 18, and 1.8 mg/l concentrations significantly reduced gross fecundity (61-85%), gross fertility (64-87%) and net fertility (85-94%) of the surviving females. In the second one, only the highest concentration achieved a significant statistical reduction in gross fecundity (52%), gross fertility (67%) and net fertility (84%). In the third assay, fecundity and fertility reduction under the two highest concentrations was 98-99% and 93-98%, whereas it was 50-74% under the 1.8 mg/l concentration, and statistically different from control values. In all three trials, treatments with 180, 18, and 1.8 mg/l concentrations significantly reduced the instantaneous rate of increase. In the third assay, treatments with the two highest concentrations caused population decline. Sublethal activity of the 0.18 mg/l concentration was not found in any assay to be statistically significant. Sublethal effects of spiromesifen and its impact on T. urticae management are discussed.
Marcic
Dejan
D
Laboratory of Applied Entomology, Institute of Pesticides and Environmental Protection, Banatska 31B, P.O. Box 163, 11080 Belgrade-Zemun, Serbia. marcion@bitsyu.net
Ogurlic
Irena
I
Mutavdzic
Slavka
S
Peric
Pantelija
P
D056810:Acaricides / Q000494:pharmacology*; D000818:Animals; D005260:Female; D005298:Fertility / Q000187:drug effects; D052287:Oviparity / Q000187:drug effects*; D010571:Pest Control; D011158:Population Growth; D013141:Spiro Compounds / Q000494:pharmacology*; D040102:Tetranychidae / Q000187:drug effects*
D056810:Acaricides; D013141:Spiro Compounds; C521569:spiromesifen