Impact of nitrogen and phosphorus fertilizer levels alone and in combination with padan insecticide on infestation of yellow stem borer, Scirpophaga incertulas Walk. in rice
1999
Rahoojo, K.M.
The experiment on the impact of various fertilizer doses alone and in combination with granular insecticides on the incidence and abundance of yellow stem borer in rice were conducted at ARI Tandojam in 1997-98 in randomized complete block design with four replicates. Each replicate comprised of ten sub- plots for respective treatments and ten lines of 5 meter length and hills were spaced at 20 x 20 cm. Forty-days old nursery was transplanted during first week of July. The fertilizer nitrogen (urea) and phosphorus (DAP) was applied in different combinations. Entire dose of fertilizer was applied during puddling i.e. one week before transplanting while half nitrogen was broadcasted one week after transplanting. The half amount of N2 was applied at the time of flowering. The granular insecticide was applied twice at morally intervals i.e. 30 and 60 days transplantation of the nursery. The observations on the number of dead hearts and white heads were recorded while selecting 20 plants at random from each sub plots. Total number of tillers and dead hearts per hill were counted after 7, 14 and 21 days of each application. White heads were recorded 25 days before the harvest of the crop. The results showed that rice borer infestation increased with plant phonology and application of insecticides alone or in combination with fertilizer doses. The higher doses of N2 increased the food material for borer.
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