Assessment of Louisiana Rice Breeding Lines for Tolerance to the Rice Water Weevil (Coleoptera: Curculionidae)

Evaluation for resistance of 40 Louisiana rice, Oryza sativa L., breeding lines to the rice water weevil, Lissorhoptrus oryzophilus Kuschel, identified several lines with tolerance to weevil damage. Six lines (8720906, 8721317, 8721937, 8722239, 8721941, and 8723514) were selected and evaluated in 1991 and 1992. Tolerance was defined as recovery from root pruning damage and production of high grain yields. Plant tolerance was assessed by evaluating the lines in replicated insecticide-treated and untreated plots. Significant differences were found among the lines tested with regard to rice water weevil larval populations, root damage ratings, plant height, and grain yields. The comparison of untreated and treated plots indicated that lines 8720906 and 8721937 exhibited moderate levels of tolerance to the rice water weevil. Lines 8722239 and 8721317 had low levels of tolerance in 1992.