الفهرس 
AcnoledgementOnly 14 pages are availabe for public view
 |  | from | 78 |  |  |
| | | from | 78 | | |
Abstract
This study aims to investigate the effectiveness
of different concentrations 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 granarium (Everts) at
various temperatures.
Results of the experiments conducted at 16, 21,
26 and 31°C and 55±5 % R.H. in the laboratory using
the following five controlled (CA) atmospheres :
1- 96 o CO2 3.2 % N2 0.8 c
°2,
1> 1>
2- 68 c CO2 25.6 c N2 6,4 ;0
°2,
1> 1> :..-0
3- 46 % CO2 43.2 % N2 10.8 ” °2, ..,;
4- 23 c CO2 61.6 o N2 + 15.4 % °2, and
1> -0
5- CA of around 99.5 c N2 + 0.5 c
°2, -0 -0
could be summarized as follows :
The exposure time required to obtain 99 %
mortality at 16°C was 17, 34, 39, 75 and 8.1 days
for the active larvae; and 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 to 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
310C 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 at the aforementioned
five controlled atmospheres, respectively.
The results indicate clearly, that the
diapausing larvae of T. granarium were more tolerant
to the various tested atmospheres than the active one
at all test temperatures.
The effectiveness of the five tested controlled
atmospheres against the active and diapausing larvae
declined with DROP in temperature. with rising the
concentration of C02 and lowering the 02 level ln the
controlled atmospheres of carbon dioxide, their
effectiveness was increased.
CA of around 99.5 % N2 + 0.5 % 02 was more
efficient in controlling the active and diapause
larvae of the Khapra beetle than CA of 96 % C02 +
3.2 % N2 + 0.8 % 02, when compared at the LT99 levels
at all test temperatures.