Time of application of insecticides against Chilo partellus (Swinhoe) on maize

An investigation was conducted during Kharif 2011 at Instructional Farm, Rajasthan College of Agriculture (MPUAT), Udaipur, for standardization of time of application of insecticide against Chilo partellus on maize. The effect of insecticide when applied immediately before or after release of larvae showed minimum Leaf Injury Rating (LIR), 1.0, maximum plant height, 169.96 and 171.85 cm, nil tunnel length and maximum plant yield, 118.27 and 119.94 g/plant, respectively. Similar significant results were obtained when larvae were released one day before and after spray. Spray of insecticide two days before or after release also resulted in less LIR, 2.87 and 2.30, plant height, 164.36 and 167.04 cm, nil tunnel length and good plant yield, 109.99 and 113.15 g/plant, respectively. The infestation of C. partellus progressively increased when spray of insecticide was made 4 to 8 DBS and 6 to 8 DAS. The release of larvae well before (8 DBS) gave high LIR, 8.70, lowest plant height, 32.76 cm, nil tunnel length and no yield.