Resistencia de dos variedades de arroz a la chinche del tallo, Tibraca Limbativentris Stål. (Hemiptera: Pentatomidae)

Rice (Oryza sativa L.) is a strategic crop for Uruguay. Among the major pests, the rice stem bug, Tibraca limbativentris (Hemiptera: Pentatomidae), stands out; it shelters at the base of rice tillers and can affect the crop during both vegetative and reproductive stages. The aim of this study was to determine the preference and the effects of rice varieties on biological traits of T. limbativentris under controlled conditions, and to complement this information with field population monitoring. Preference (antixenosis) was evaluated through free-choice tests on four rice varieties: INIA Olimar, Gurí INTA CL, INIA Cuareim (SLI09197), and SLI09193. For this purpose, 16 plants (randomly arranged from the four varieties) were set up and four T. limbativentris females were released; their choice was recorded from 0.5 to 48 h. Biological traits (antibiosis) were assessed under laboratory conditions on INIA Cuareim (SLI09197) and SLI09193, recording the duration of each developmental stage, total developmental time, and survival capacity. Field population monitoring was conducted through monthly visits (October–March) at a commercial farm in northern Uruguay during the 2023/24 and 2024/25 growing seasons, in INIA Olimar and INIA Merín, at 10 sampling points using a 1 m² quadrat. In the preference assays, females showed higher selection for Gurí INTA CL and INIA Cuareim (SLI09197), whereas SLI09193 was the least selected material; INIA Olimar also showed low selection, suggesting non-preference. In the biological assays, performance was similar between INIA Cuareim (SLI09197) and SLI09193; survival to adulthood was low in both varieties, but even lower in SLI09193. Total developmental time was longer in INIA Cuareim (SLI09197) than in SLI09193 (x̄ = 6.35 days; p = 0.0001). In field evaluations, population abundance was strongly conditioned by phenological stage and interannual variation, with low presence during the vegetative stage. During the reproductive phase—especially in the 2023/24 season—higher pest presence and differences between varieties were observed, with higher population levels in INIA Merín than in INIA Olimar (ratio = 2.29; p = 0.0003). This study integrates evidence on behavior, biological performance, and field dynamics, showing that T. limbativentris responses depend on plant material and crop timing. The results reinforce the importance of monitoring during reproductive windows and provide inputs to discuss the use of less attractive and/or less suitable varieties as hosts within integrated pest management strategies supported by local evidence. These results constitute a baseline and may guide future evaluations of varietal resistance and adjustments to management strategies and intervention thresholds.