Effect Of Planting Time And Nitrogen Levels On Infestation Of Rice By African Rice Gall Midge Orseolia Oryzivora Harris And Gagné In Southeastern Nigeria

Abstract

Field experiments were conducted to evaluate the effect of time of planting (July 14, August 11 and September 8) and varying nitrogen levels (0, 80 and 160 N/ha) on infestation of rice by African rice gall midge and grain yield. The experiments were conducted at West African Rice Development Association (WARDA) research farm at Ogidiga near Abakaliki during the wet seasons of 2002 and 2003 farming seasons. The rice variety used for the experiments was ITA 306. Percentage infestations of rice by African rice gall midge were significantly highest on rice planted on July 14. Percentage infestations by African rice gall midge also significantly increased with the increasing levels of nitrogen up to 160 kg N/ha irrespective of time of planting. Results show that grain yields were highest on rice planted on August 14 for both seasons. However, the response of grain yield to nitrogen was optimum at 80 kg N/ha. Further increase in nitrogen did not cause any significant different in grain yield for both seasons.

Keywords: Time of planting, Nitrogen levels, Infestation, Rice, African Rice Gall Midge

Journal of Technology and Education in Nigeria Vol. 10 (1) 2005: pp. 39-45