Phytoseiid mites, mainly Neoseiulus californicus (McGregor), are important biological control agents of Tetranychidae pest mites in pip fruit crops in the region known as "Alto Valle del Río Negro y Neuquén", Argentina. We assessed the mortality of N. californicus when exposed to residues of the insecticides azimphos-methyl, carbaryl and cyfluthrin, as well as the acaricides cyhexatin and propargite. Pear plants were sprayed up to dip-point with pesticides in their recommended label concentrations. One, 3, 6 and 10 days after application (DAA), leaves were collected from treated plants and used to establish experimental arenas. Five adult laboratory-reared N. californicus specimens were transferred into each arena which contained Southern cattail pollen as food source. Experimental arenas were kept at 25 ± 2 ºC, 60 ± 10% RH and a photoperiod of 14 hours. Mite mortality was assessed 24 hours after the confinement. The completely randomized design was adopted for data statistical analysis, mortality means were compared by Dunnett's test (p < 0.05). Progression of pesticide's effect decline was submitted to regression analysis. On 1 and 3 DAA mean mortality in all of the treatments was significantly different from that of the water-treated control. On the sixth DAA, propargite, cyhexatin and cyfluthrin treatments caused about 30% mortality, while mortality levels in treatments with azimphos-methyl and carbaryl were statistically similar to that of control treatment. On the tenth DAA, mortality in none of the pesticide treatments differed from that of control. All of the pesticide treatments presented progressive decline throughout the experimental period, being significant (p < 0.01) the negative linear regression obtained. Tested acaricides produced the greatest negative effects on the survival of N. californicus. Azimphos-methyl was the pesticide that least affected the survival of the predatory mite. Tested insecticides, used in the "Alto Valle del Río Negro y Neuquén" region to control codling moth, C. pomonella, key pest of pip fruit crops, showed low toxicity to N. californicus.
Biological Control; Integrated Pest Management; Selectivity; Pip fruit
