1Central Horticultural Experiment Station, Chettalli, Kodagu-571 248, Karnataka, India.
2Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad-580 005, Karnataka, India.
Chilli yield loss assessment due to the fruit borer Helicoverpa armigera (Hubner) on plants in green house and field conditions. Under green house condition in potted plants, the observed percentage fruit damage was zero, 13.46,21.30,31.18,40.00, 46.65 and 49.30 with 0,1,2,3,4,5 and 6 larvae per plant respectively. Yield reduction due to individual larva was 2.5 q/ha. Further, it was evident that 2,3,4,5 and 6 larvae resulted in yield reductions of 4.26,6.23,7.77,9.07 and 9.99 q/ha. In field experiment, it was revealed that the fruit damages were zero, 11.68,18.84,25.00,31.25,40.27 and 50.00 at 0,1,2,3,4,5 and 6 larval load per plant respectively. The yield reduction for 1,2,3,4,5 & 6 larvae per plant was zero, 2.49,3.61,4.72,6.94, 8.05 and 11.11 q/ha respectively.
Based on regression equation, for every increase in larval number per plant the increase in damage to fruits was 7.87%, while yield decreased by 171 q/ha. The regression equation based on the cost of plant protection measures against the pest and market price of the produce projected that the economic threshold of H. armigera in chilli was 1.46 larvae/plant.
Chilli, Helicoverpa armigera
