Biocontrol Science and Technology (2008) 18, 1027-1040

Carlo Duso, Valeria Malagnini, Alberto Pozzebon, Filippo Maria Buzzetti and Paola Tirello (2008)
A method to assess the effects of pesticides on the predatory mite Phytoseiulus persimilis (Acari Phytoseiidae) in the laboratory
Biocontrol Science and Technology 18 (10), 1027-1040
Abstract: Phytoseiulus persimilis Athias-Henriot (Acari Phytoseiidae) is a major predator of Tetranychus urticae (Acari Tetranychidae). The performance of P. persimilis in controlling T. urticae may be altered by pesticides used to manage other pests. Therefore, knowledge of the side-effects of pesticides is essential for IPM. A number of laboratory methods were suggested to evaluate pesticide side-effects on predatory mites. Most methods assess residual effects only, and a number of them are characterised by high predator escape rates from experimental units. A method aimed at evaluating the topical and residual effects of pesticides on P. persimilis is herein described. Mites were treated by microimmersion and then reared in holding cells, on bean leaves previously dipped in a pesticide solution. Three insecticides (pyrethrins, spinosad and thiamethoxam), an insecticide-acaricide (abamectin), and two fungicides (azoxystrobin and tolylfluanide) were evaluated. The strain of P. persimilis used for evaluation was collected from unsprayed vegetable plants. All the pesticides affected the survival and fecundity of P. persimilis. Pesticides did not affect the egg-hatching of P. persimilis females exposed to pesticides. Pyrethrins and abamectin proved to be more toxic than other pesticides, and thiamethoxam was more toxic than spinosad, azoxystrobin and tolylfluanide. The escape rate from experimental units was lower than 5% in all trials. Additional experiments were performed on P. persimilis eggs by dipping leaves with eggs in the pesticide solution. None of the pesticides affected egg survival. Semi-field trials conducted on potted bean plants obtained results similar to those reported in laboratory trials.
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Link to article at publishers website
Database assignments for author(s): Carlo Duso, Alberto Pozzebon

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
health/environmental effects of pesticides
Research topic(s) for beneficials or antagonists:
resistance to pesticides

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae
Phytoseiulus persimilis (predator)	Tetranychus urticae