Triflumuron: Residual Activity and Ovicidal Longevity in the Rice Water Weevil (Coleoptera: Curculionidae)

Abstract

Lissorhoptrus oryzophilus Kuschel adults were exposed to foliage of rice, Oryza sativa L., sprayed with a triflumuron-water suspension (0.28 kg [AI]/ha) to evaluate the residual control capabilities of foliar residues and to determine the longevity of ovicidal activity. Weevils were placed on treated plants at 1, 3, 5, and 7 d following application in 1985 and at 1, 3, and 5 d following application in 1986. Significant decreases in the number of larvae occurred for day 1 through day 3 in 1985 and for day 1 through day 5 in 1986 when compared with untreated checks. A significant reduction in the eclosion of first instars was observed for up to 4 d after a 24-h adult exposure period. There were no significant differences in the number of unhatched eggs remaining in the rice sheath, but there was a trend for more eggs-27.6-55.6% more than found in the check-to be found in the treated plants. Rice plants containing O-I-d-old eggs laid by unexposed adults were placed in water removed from a field that had been treated with triflumuron. The water was removed 1, 2, and 3 d after application to evaluate the extended control capabilities of residues. Significant reductions in larval numbers occurred for day 1 only.