Nitrogen fertilization at the rice panicle differentiation stage to compensate for rice water weevil (Coleoptera: Curculionidae) injury

• Published in: Crop protection 2008, Vol.27 (1), p.84-89
• Main Authors: Reay-Jones, F.P.F., Way, M.O., Tarpley, L.
• Format: Article
• Language: English
• Subjects: application timing; Compensation; crop damage; developmental stages; fertilizer application; fertilizer rates; field experimentation; inflorescences; insect control; insect pests; Lissorhoptrus oryzophilus; Nitrogen fertilizer; nitrogen fertilizers; Oryza sativa; Rice; Rice water weevil
• ISSN: 0261-2194; 1873-6904
• DOI: 10.1016/j.cropro.2007.04.009

A three-year study was conducted to determine the effect of nitrogen fertilizer rates applied at the panicle initiation stage of rice, Oryza sativa L., and insecticide applications on yield loss caused by rice water weevil, Lissorhoptrus oryzophilus Kushel, damage. Our estimates of yield loss caused by L. oryzophilus injury were, at the recommended nitrogen rate of 191 kg N per ha, 1.7% in 1997, 11.8% in 1998, and 9.9% in 1999. In 1998, doubling the panicle differentiation nitrogen rate from 67 to 134 kg N per ha significantly increased yield by 591 kg per ha, averaged across insecticide treated and untreated plots. In both 1998 and 1999, reducing nitrogen rate below the recommended rate significantly ( P0.05) for yield in any year of our study, suggesting that increasing nitrogen at the panicle differentiation stage does not have a major impact on compensation of the rice plant for L. oryzophilus injury. Our results indicate that farmers should not increase nitrogen fertilizer at the panicle differentiation stage to compensate for L. oryzophilus damage.