Combination of Microwaves Radiation and Cold Storage for Control of Oryzaephilus surinamensis (L.) (Col. Silvanidae)

The effect of microwaves radiation and cold storage against adults of sawtoothed grain beetle, Oryzaephlius surinamensis (L.) over various exposure times and cold storage period was evaluated. The insects were exposed to 2450 MHz at five different power levels of 0, 100, 200, 300 and 400 W for five exposure times of 0, 3, 6, 9 and 12 min. A complete mortality was achieved for tested insect at 400 W power level for exposure time of 12 min and 72 h cold storage period. At a given time, a direct positive relationship between mortality rates and microwaves radiation power level was obtained. For instance at 100, 200, 300 and 400 W power levels and 24 h cold storage for 3 min exposure period, the mortality rates were 40, 50, 55 and 72%, respectively. Similar trend was obtained for LT sub(50) values. Considerable variation in the susceptibility of tested insect to microwaves power levels and cold storage periods was apparent in the fiducial limits of the LD sub(50), values. In the analysis of variance (ANOVA) the R super(2) value revealed that 90.8% of variability in the susceptibility of O. surinamensis could be explained by the microwaves power, cold storage period and exposure duration. Combinations of microwaves radiation and cold storage were found highly compatible and synergistic. This was more significant for the insects which were exposed to the highest level of microwaves radiation and cold storage period. Synergistic interaction indicates that microwaves radiation can be used with cold storage for management of O. surinamensis. This treatment could provide an effective and friendly environmental treatment technique in IPM program.