Susceptibility of some Indian sorghum varieties to angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae)

Abstract

The susceptibility of some Indian sorghum varieties to the Angoumois grain moth, Sitotroga cerealella (Olivier) was investigated in the laboratory at a temperature of 28.0±2.0°C and relative humidity of 65.0±1.5%. The sorghum varieties tested included CSV 15, AVHT 303, AVHT 310, AVHT 313, AVHT 328, AVHT 644, AVHT 646, IHT 405, IHT 419 and IHT 424. In the first experiment, 100 (0-24h old) eggs of S. cerealella were used to infest twenty grammes of each sorghum variety while in the second experiment 0-24h old adults were paired in glass vials. Results showed that IHT 405, an initial variety (experimental), with longest developmental time (29.7days) and least percent survival of egg to adult of 20.6% was the least susceptible variety to S. cerealella infestation while CSV 15, with shortest developmental time (26.7days) and highest percent survival of egg to adult of 47.4%, had highest susceptibility. The weight of newly emerged adults ranged from 1.55g (AVHT 313) to 2.09g (AVHT 310) in males and 2.79g (IHT 405, 419) to 3.93g (IHT 424) in females. Virgin females lived longer than their mated counterparts while females generally lived longer than males. Significant differences were found in the number of eggs laid. Fecundity was highest (130eggs/female) in AVHT 303 and lowest (96eggs/female) in IHT 405. Hatchability ranged from 88.0% in AVHT 644 and 97.2% in AVHT 646.

Key words: fecundity, hatchability, Sitotroga cerealella, sorghum, susceptibility