Influence of Different Rice Cultivars on Schizotetranychus oryzae Development.

Schizotetranychus oryzae Rossi de Simons (Acari: Tetranychidae) is considered one of the most important phytophagous mite in rice cultivation in the Americas South, Central, and North. This study aimed to examine some biological aspects of S. oryzae developing on leaves of three different cultivars of rice [Oryza sativa (L.)-Poaceae] produced in the state of Rio Grande do Sul, Brasil. The plants were kept in a room at 25 ± 1°C, with natural light (photophase of approximately 14 h) and 70 ± 5% relative humidity. During the immature stages, observations were carried out daily at 7 am, 1 pm, and 7 pm. The results showed that the mean duration of the egg-adult period in days were similar between cultivars evaluated (Irga 424, 11.27 ± 0.13; Taim, 11.21 ± 0.14 and Sinuelo, 11.13 ± 0.15). Egg-adult viability on Irga 424, Sinuelo, and Taim was 61.9, 85.71, and 90.48%, respectively, being lowest on Irga 424 (χ2 = 28.62, p < 0.0001). The duration of the immature stages was not affected by cultivar, but on Irga 424, egg-adult viability and female longevity were lower. The results of this study can help select O. sativa cultivar resistant to S. oryzae. However, historically, the IRGA 424 has lower populations of S. oryzae in field conditions.