Effect of carbon dioxide rich atmosphere on storage insects and fungi.

An experiment was conducted during 2003-05 at New Delhi to study whether modified atmosphere with higher carbon dioxide concentration can protect seeds with higher moisture content from insect and fungal infestation. Different carbon dioxide concentrations (20, 40, 60 and 80%) and longer exposure periods (4, 8 and 12 months) were tested against storage insects [rice weevil (Sitophilus oryzae) and lesser grain borer (Rhyzopertha dominica)] and storage fungi. The LC 50 values of CO 2 were 15.67, 13.97 and 10.97% (v/v) at 15, 20.8 and 30.5°C respectively with an exposure period of 72 hr. All the carbon dioxide concentrations tested completely controlled insect population build-up and insect damage in rice seed. The carbon dioxide concentrations of 60 and 80% reduced fungal incidence but none of the carbon dioxide concentrations tested completely controlled fungal infestation in rice seeds.