-Despite the importance of peach (Prunus persica (L.) Batsch) in Rio Grande do Sul, little is known about mites fluctuation population considered important to this crop. The objective of this study was to know the population diversity and fluctuation of mite species associated with Premier and Eldorado varieties in Roca Sales and Venâncio Aires counties, Rio Grande do Sul. The study was conducted from July 2008 to June 2009 when 15 plants were randomly chosen in each area. The plants were divided in quadrants and from each one a branch was chosen from which three leaves were removed: one collected in the apical region, another in the medium and the other in the basal region, totalizing 180 leaves/area. Five of the most abundant associated plants were collected monthly in enough amounts for the screening under the stereoscopic microscope during an hour. A total of 1,124 mites were found belonging to 14 families and 28 species. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836 and Mononychellus planki (McGregor, 1950) were the most abundant phytophagous mites, whereas Typhlodromalus aripo Deleon, 1967 and Phytoseiulus macropilis (Banks, 1904) the most common predatory mites. The period of one hour under stereoscopic microscope was enough to get a representative sample. In both places evaluated the ecologic indices were low, but little higherin Premier (H' 0.56; EqJ: 0.43) when compared to Eldorado (H' 0.53; EqJ 0.40). In Premier constant species were not observed and accessory only Brevipalpus phoenicis (Geijskes, 1939), T. ludeni and T. aripo. Higher abundance was observed in December and January and bigger amount in April. Already in Eldorado, T. ludeni and P. ulmi were constants. Greater abundance was observed in November and December, whereas grater richness in December and January. In both orchards were not found mites in buds. Tetranychus ludeni is the most abundant phytophagous mites with outbreak population in November, December and January and high predator diversity was observed on associated plants and on peach plants, indicating the existence of species mobility in peach orchard. Index terms: Acari, biological control, Panonychus ulmi, Tetranychus ludeni, Typhlodromalus aripo.
FLUTUAÇÃO POPULACIONAL DE ÁCAROS NA CULTURA DO PESSEGUEIRO (Prunus persica (L.) Batsch) E EM PLANTAS ASSOCIADASRESUMO -Apesar da grande importância da cultura do pêssego [Prunus persica (L.) Batsch] no Rio Grande do Sul, pouco se conhece sobre a diversidade e a flutuação populacional de ácaros considerados importantes para esta cultura. O objetivo deste trabalho foi conhecer a flutuação populacional das espécies acarinas associadas às cultivares Premier e Eldorado nos municípios de Roca Sales e Venâncio Aires, Rio Grande do Sul. O estudo foi realizado no período de julho de 2008 a junho de 2009, quando foram amostradas 15 plantas escolhidas ao acaso numa área em cada município. As plantas foram divididas em quadrantes, e de cada quadrante foi escolhido um galho de onde foram retiradas três folhas das regiões...