Mortality of Sitophilus oryzae (L.) and S. granarius (L.) in atmospheres produced by an exothermic inert atmosphere generator

The exposure to atmospheres with low O₂ required to kill 50 and 95% of the developing Sitophilus oryzae (L.) and S. granarius (L.) indicated that the earlier and later stages were more susceptible and the middle stages were less susceptible. At 27°C, the duration of exposure required to produce 95% mortality during the 4th instar through early pupal development was about 10 days for S. oryzae and 6 days for S. granarius. The toxicity of the atmosphere produced by an exothermic inert atmosphere generator to each stage of S. oryzae was higher at 27°C than at 21°C. Larvae and pupae of S. granarius were more susceptible to the atmosphere than corresponding stages of S. oryzae. The type of grain in which the S. oryzae were developing did not significantly alter the mortality due to the generated atmosphere.