Division of Entomology, Indian Agricultural Research Institute, New Delhi-110 012 (India).
During kharif 1993, severity of damage due to the American bollworm, Heliothis armigera (Hubner), was observed on sorghum. The population of larvae varied from 1 to 8 per earhead. The larvae were observed feeding on tender grains, leaving empty glumes in young earheads. Also, fully grown larvae consumed other tender parts of the earheads. In severe infestation, large portions of young earheads with developing grains were completely devoured, resulting in half developed earheads. Open-type sorghum earheads were less preferred as compared to compact earheads. Selfed earheads (covered with paper or muslin cloth bags) were more damaged and showed the presence of pupae, though normal pupation is in soil. Out of the nineteen promising genotypes of sorghum, only three, viz., P362, P300 and 372 x 5490 showed relatively less damage as compared to other genotypes indicating varietal influence over the abundance and distribution of H. armigera. The sorghum genotype 5490 x 302 was the most susceptible entry followed by P100. Collection of over 713 pupae on three consecutive days from sorghum grown in one acre of land, highlights the >potentiality of this crop as a host for H. armigera, in future.
