Fluctuation of Mite Fauna Associated to Rice Culture (Oryza sativa L.: Poales, Poaceae) in Two Regions in the State of Rio Grande do Sul, Brazil

This survey had the aim to identify the mite fauna and mite ecologic interaction in rice culture, harvest 2010-2011, in Taquari and Cachoeirinha Counties, state of Rio Grande do Sul, Brazil. The mite population was biweekly evaluated on IRGA 424 and INTA PUITA CL cultivars in four areas where randomly sampled 20 plants/area. Fluctuation, ecologic indices and correlation between species and environmental factors were calculated. A total of 1,626 mites belonging to 14 species from 12 families were collected. Of the total specimens collected, 34.56% was on IRGA 424, in Taquari, 32.47% on IRGA 424-120 and 28.35% on IRGA 424-60, in Cachoeirinha and 4.61% on INTA PUITA CL, in Taquari. Family Ascidae showed great richness, with four species, Lasioseius sp., Lasioseius sp., Proctolaelaps sp. and Cheiroseius sp.. Schizotetranychus oryzae Rossi de Simons (86.65%) was the phytophagous mite more abundant, while among the predators Neoseiulus paraibensis (Moraes and McMurtry) (6.88%) stood out. The population peaks of S. oryzae and N. paraibensis happened on March 2011. In all evaluated areas, the correlation between S. oryzae and N. paraibensis was positive, specially on IRGA 424-120 (r = 0.93, P = 0.006).