Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560 089.
Action thresholds for initiating insecticide spravs based on per cent new damage on the head and appearance of egg masses of leafwebber were evaluated in comparison with fixed weekly and fortnightly sprays. There was no significant difference in the marketable yield recorded between plots maintained with thresholds of 3 and 5% new damage and fixed spray programmes. Adoption of both the thre-sholds resulted in reduced number of sprays. Use of thresholds based on appearance of egg masses of leafwebber alone resulted in loss of marketability. Results of this study further indicated a need to evolve suitable threshold if there is early build up of pest during preheading stages.
