Some effects of plant densities and carbofuran on the damage by Diopsis thoracica West,and Maliarpha separatella Rag. and yield of rice in Nigeria

Abstract

In a field study of the effects of plant densities and carbofuran on damage by Diopsis thoracica Westwood and Maliarpha separatella Ragonot, significant increases were recorded in the percentage of dead hearts and bored stems in widely spaced rice plants. Carbofuran treatments resulted in significant control of borers, the best treatment being that covering early growth up to 40 days after transplanting. There was a significant depression of yield components and total yield with closer spacing. Yield increases of 59%, 32% and 55% for the 1983 planting, and 55%, 35% and 50% for the 1984 planting, were recorded when carbofuran was applied to cover the periods 0 to 40, 40 to 80, and 0 to 80 days after transplanting, respectively.The percentage of dead hearts and bored stems increased with increasing seedling density. The yield components, however, did not show any significant differences.