Forty-eight methods were tried out to evaluate the efficiency of each regarding preventing the individuals of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) from exiting the area allocated to them in the laboratory.
The most efficient method was based on surrounding that area with a 5-millimeter-high plastic wall and laying a thin cotton thread on the outer bevel of the wall top, besides saturating the thread continuously with phosphoric acid 3%. There was a groove around the wall; meanwhile, there was a narrow space between the wall and the groove. The groove was filled with phosphoric acid 3%. One of the thread tips was immersed in the diluted acid located in the groove to ensure continuous saturation. Over 24 hrs., no mite individual could pass across the wall, but 0.33% of the individuals stuck to the thread. In contrast, by saturating the thread with water, 4.33% of the mite individuals could pass across the wall, and 2% of the mite individuals stuck to the thread.
The least efficient method was based on surrounding the area allocated to the mites with a groove and filling it with citric acid 25%. Over 24 hrs., no mite individual could pass across the groove, but 7% of the mite individuals drowned in the surrounding acid. In contrast, when filling the groove with water, no mite individual could pass across the groove, but 4% of the individuals drowned in the surrounding water.