This study aims to investigate the effectiveness of different
concentratiops of carbon dioxide in controlled (modified) atmospheres as well as
a controlled atmosphere of more than 99 % nitrogen in controlling the active
and diapausing larvae of the Khapra beetle. Trogoderma granariurn (Evens) at
various temperatures. Results of the experiments conducted at 16, 21. 26 and
31 oc and 55±5 % R.H. in the laboratory using the following five controlled
(CA) atmospheres :
l-96%C02 : 3.2%N2 : 0.8%02
2-68%C02 25.6 %N2 : 6,4%02
3- 46 % CO2 : 43.2 0/ N2: 10.8 % 02
4-23 %C02 :61.6 %N2+ 15.4 %02
5- CA of around 99.5 % N2 + 0.5 % 02
Showed the following : The exposure time required to obtain 99 % mortality at
،6°C was 17, 34, 39, 75 and 8.1 days for the active larvae; ًnd 25.6, 38, 46, 109
and 11.1 days for the diapausing larvae at the different aforementioned
atmospheres, respectively. Exposure periods needed to achieve 99 % kill at
21°C were 13.9, 23.1, 48.5, 62.5 and 7.3 days for the active larvae: and 21.6.
29.8. 58.0, 61.6 and 7.4 days for the diapause one at the various CA,
respectively.
Time recorded lo achieve 99 % mortality at 26°C was 8.9, 16.5, 20.3,
36.7 and 5.7 days for the active larvae and 10.7, 24.0, 36,4, 47.1 and 5.9 days for
the diapausing larvae at the aforementioned CA, respectively. Exposure periods
needed for 99 % mortality at 31°C were 7.8, 10.8. 18.7, 22.7 and 4.2 days for the
active larvae: and 10.3. 20.1. 30.3, 42.0 and 5.7 days for the diapausing larvae ai
the aforementioned live controlled atmospheres, respectively.
The results indicate clearly, thai the diapausing larvae of T granarluin
were more tolerant to flic various tested atmospheres (hait the active one ai all