Experimental and Applied Acarology (2017) 71, 211-226

Asma Musa, Irena Medo, Ivana Maric and Dejan Marcic (2017)
Acaricidal and sublethal effects of a Chenopodium-based biopesticide on the two-spotted spider mite (Acari: Tetranychidae)
Experimental and Applied Acarology 71 (3), 211-226
Abstract: Acaricidal and sublethal effects of the biopesticide Requiem^®EC (containing an essential oil extract of Chenopodium ambrosioides near ambrosioides) on the two-spotted spider mite, Tetranychus urticae Koch, were evaluated in laboratory bioassays. The biopesticide was applied to bean leaves or leaf discs using a Potter spray tower. Acaricidal activity against eggs and immatures was evaluated in successive acute toxicity bioassays. Concentration-mortality data were subjected to probit analysis and the following LC₅₀ values (ml/l) were calculated: 2.47 (eggs), 0.71 (larvae), 1.13 (protonymphs), 2.23 (female deutonymphs), and 6.02 (female teleiochrysalises). In adult bioassay, in which pre-ovipositional females were treated with a series of concentrations (0.31–10 ml/l), a run-off effect ranging 4–80% (after 24 h) and 8–93% (after 72 h) was observed. In two-choice bioassay, T. urticae females preferred the untreated halves of leaves over the halves treated with 1.25–10 ml/l biopesticide and they laid significantly more eggs on the untreated halves in the first 24 h and summed over 72 h. The indices of repellency and oviposition deterence ranged 11.2–77.3 and 14.8–87.9%, respectively. In age-stage two-sex life table bioassay, the females that hatched from eggs treated with 2.5 ml/l biopesticide and reached adulthood on treated leaf surface showed a significantly reduced the intrinsic rate of increase (r = 0.222),compared to the control (r = 0.317).The reduction of population growth was mainly due to a reduced preadult survival rate (0.42 ± 0.04) and extended juvenile developmental time (9.27 ± 0.11 days), compared to the control (0.93 ± 0.03 and 7.70 ± 0.06 days, respectively).
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Dejan Marcic

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae