Laboratory experiments of vacuum treatment in combination with an O2 absorber for the suppression of Sitophilus granarius infestations in stored grain samples

• The efficacy of vacuum alone versus in combination with an oxygen absorber on grain pests was studied.
• Both treatments significantly increased the mortality of S. granarius.
• Adults in the grain interspaces were more susceptible than the hidden individuals.
• A higher temperature and a prolonged exposure time enhanced treatment efficacy.
• Use of an oxygen absorber in combination with vacuum treatment improved efficacy.

The effectiveness of vacuum (V) treatment alone and in combination with an oxygen absorber (V + A) for suppression of grain infestation by Sitophilus granarius L. were compared under laboratory conditions. The effectiveness of the treatment methods was evaluated at different temperatures (15, 25 °C) and exposure times (7, 14, 21, 28 days). We evaluated both the effects on adults present in grain interspaces and hidden infestations within the kernels in terms of treatment time separately. Adults of S. granarius present in grain interspaces were more susceptible to both treatments than hidden infestations developing within kernels. At 25 °C, total mortality of adults in grain interspaces was achieved after 10 days of exposure whereas total suppression of hidden infestations was achieved after 3 weeks. Higher temperature and longer exposure correlated with a greater effectiveness of the tested treatments. The addition of an oxygen absorber to the vacuum treatment (V + A) showed the general tendency of improving the effectiveness of the vacuum treatment on suppression of hidden infestations; significant differences between the V + A and V treatments were prominent primarily at the lower temperature tested. Reduction of hidden infestation was achieved after 3 weeks of exposure to V + A treatment (99.8%) and after 4 weeks of V treatment (95.8%) at 15 °C.