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Abstract [Objective] This study aimed to investigate the killing effect of mixed fumigation of phosphine and carbon dioxide on eggs of Lasioderma serricorne F. [Method] The outside-storage phosphine generator was placed in a tabernacled smoke box, and the mortality rates of L. serricorne F. eggs in the smoke box under conditions of different aluminium phosphide usage amount and different fumigation time were studied. In addition, the times needed by tabernacle and smoke box center to reach the phosphine concentration peak were recorded. [Result] The optimum conditions for killing the eggs of L. serricorne were as follows: temperature of (27± 2) °C, relatively humidity of (45±5)%, aluminium phosphide usage amount of 1.5 g/m3 and effective exposure time of 96 h. The killing effect of mixed fumigation of phosphine and carbon dioxide was increased with the extension of fumigation time. The increased usage amount of aluminium phosphide showed no significant effect on killing effect. The tabernacle space and smoke box center all required relatively short time to reach the phosphine concentration peak. If the tabernacle had a good airtightness, the overall fumigation time could be shortened. [Conclusion] The fumigation method is reliable, and it can be used for the control of L. serricorne F. in tobacco storage.
Key words Mixed fumigation of phosphine and carbon dioxide; Lasioderma serricorne F.; Egg; Fumigation time; Mortality rate
Phosphine fumigation is the most widely used insecticidal method for various tobacco processing enterprises during tobacco storage period. Related researches have shown that carbon dioxide can enhance the penetrability of phosphine, making phosphine uniformly distributed in the fumigation space1'1. In addition, carbon dioxide can stimulate the breath of insects, thereby enhancing the killing effect on insects121. To improve the fumigation effect, shorten the fumigation time and reduce phosphine's deflagration risk, mixed fumigation of phosphine and carbon dioxide for killing insects in stored tobacco has been promoted in many areas. However, there are rare reports on killing effect of mixed fumigation of phosphine and carbon dioxide on insects.
L. serricorne F. is one of the main pests in tobacco at the alcoholization stage. The mortality rate of eggs of L. serricorne F. is an important indicator evaluating fumigation effect. In this study, under the conditions of different fumigation time and concentration of...