Influence of levels and sources of nitrogen on the incidence of leaf folder, Cnaphalocrocis medinalis Guen. in different rice varieties*

The influence of levels and sources of nitrogen on the incidence of leaf folder, Cnaphalocrocis medinalis Guen. in different varieties of rice was studied in shallow low land situation. Among the six varieties, viz., IET 9746, IET 9188, IET 9572, Radha, Rajshree and Salivahana, and three levels of nitrogen (20, 40 and 60 kg N/ha), each from two sources, viz, urea and urea super granule, it was observed that at 60 days after transplanting Salivahana (12.19%) was least susceptible, whereas IET 9572 (25.01%) was the most susceptible against the rice leaf folder. There was corresponding and significant increase in infestation of the rice leaf folder with the increase in levels of nitrogen for both the sources, when observations were recorded both 30 and 60 days after transplanting. But the sources of nitrogen were at par statistically in respect of incidence of leaf folder.