Effect of nitrogen and potash on Early shoot borer (Chilo infuscatellus Snellen) incidence in differently maturing varieties of sugarcane

It has been argued that fertilization may influence the susceptibility of insect pests, and thus, can increase the crop production by lowering the incidence of insect-pest. Here, the present investigation was carried out to study the influence of nitrogen and potash levels on the incidence of early shoot borer, Chilo infuscatellus Snellen in sugarcane varieties at Regional Research Station CCSHAU Uchani farm, Karnal. The experiment was laid out in split-split plot design with three differently maturing varieties viz., Co 0238, CoH 119 and CoH 150 as main plot, three doses of nitrogen viz., 150, 200 and 250 kg per hectare (kg/ha) as sub plot and two doses of potash viz., 0 and 50 (kg/ha) as sub-sub plot. The early shoot borer mean per cent incidence recorded in April, May and June, 2015 was highest (7.68, 12.19 and 6.35, respectively) in Co 0238 while, lowest (5.16, 8.51 and 5.40, respectively) in CoH 119 followed by CoH 150 (6.29, 8.79 and 5.43, respectively). In relation to nitrogen application, maximum mean per cent incidence (7.12, 11.19 and 6.48, respectively) in April, May and June, 2015 of early shoot borer was recorded at 250 kg N/ha and the minimum (5.68, 8.57 and 5.23, respectively) at 150 kg N/ha. Application of potassium significantly reduced the shoot borer infestation with mean per cent incidence lower at 50 kg K2O/ha (5.90, 9.24 and 5.33, respectively) in April, May and June, 2015 compared to control i.e., no application of potassium (6.85, 10.42 and 6.12, respectively). Results revealed that application of potassium with optimum dose of nitrogenous fertilizer along with selection of suitable variety acted as preventive measures to avoid shoot borer infestation