The Effects of Kingbo Biopesticide on Tetranychus urticae Koch Female Adults
Efekti biopesticida Kingbo na odrasle ženke Tetranychus urticae Koch
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Author
Medjo, Irena
Marcic, Dejan
Keywords
Sublethal effectsOxymatrine
Tetranychus urticae
Biopesticides
Subletalni efekti
oksimatrin
biopesticidi
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Show full item recordAbstract
Toxic and sublethal effects of the biopesticide Kingbo (oxymatrine 0.2% + psoralen
0.4%) on female adults of two-spotted spider mite (Tetranychus urticae Koch) were investigated
in two laboratory bioassays. The assays were set up in four replicates on bean
leaf discs (30 mm in diameter) placed on moistened cotton wads in Petri dishes. Preovipositional
females were then released on them and treated directly with the biopesticide
at a concentration series using a Potter device (2 ml liquid, 100 kPa air pressure, 2.7 ±
0.2 mg/cm2 aqueous deposit). Each replicate included 4-7 Petri dishes containing a total
of 20-35 females. In the first assay, females were exposed to continuous acaricidal activity
on treated discs over a period of 96 h; in the second assay, they were exposed for 24 h
and then transferred to untreated discs and kept there for the next 72 h. Kingbo toxicity to
females, expressed as LC50, was significantly higher in the first bioassay (14.83 μl/l) than in
the second one (26.39 μl/l). Total gross fecundity of females in the first assay was reduced
by 37-95% and net fecundity by 48-97%, depending on concentration; in the second assay,
the respective fecundity reductions were 15-87% and 23-91%. We found that a 24 h exposure
to the biopesticide Kingbo was sufficient for sustaining significant toxic and sublethal
effects. Further research should provide additional data on the recovery potential of T. urticae
populations. Toksični i subletalni efekti biopesticida Kingbo (oksimatrin 0,2% + psoralen 0,4%) na
odrasle ženke obične paučinaste grinje (Tetranychus urticae Koch) ispitivani su u dva laboratorijska
ogleda. Ogledi su izvedeni u četiri ponavljanja na kružnim lisnim isečcima primarnih
listova pasulja (prečnika 30 mm) postavljenim u petri-sudove na navlaženu vatu, na kojima
su pre-ovipozicione ženke direktno tretirane serijom koncentracija biopesticida pomoću
Poter-aparata (2 ml tečnosti, pritisak 100 kPa, vlažni depozit 2,7 ± 0.2 mg/cm2). Tretirano je
4-7 petri-sudova sa 20-35 ženki po ponavljanju. U prvom ogledu ženke su bile 96 h kontinuirano
izložene delovanju akaricida na tretiranim isečcima, dok su u drugom ogledu posle
24 h prebačene na netretirane isečke, gde su ostale naredna 72 h. Na nivou LC50, utvrđena
je značajno veća toksičnost biopesticida Kingbo za ženke u prvom ogledu (14.83 μl/l) u poređenju
sa ženkama u drugom ogledu (26.39 μl/l). Ukupan bruto-fekunditet ženki u prvom
ogledu redukovan je za 37-95%, a neto-fekunditet za 48-97%, u zavisnosti od koncentracije;
u drugom ogledu odgovarajuća redukcija fekunditeta iznosila je 15-87% i 23-91%. Konstatovano
je da je 24-časovna ekspozicija biopesticidu Kingbo dovoljna za nastajanje značajnih
toksičnih i subletalnih efekata, kao i da su potrebna dalja istraživanja u cilju preciznije
procene potencijala oporavka populacije T. urticae.