Fumigant Effect of Three Kinds of Oganophosphorus Insecticides against Larva of Ephestia elutella( Hübner)

The control of stored tobacco pests in farm storehouse of China mostly depended on the fumigant activities of some organophosphorus insecticides,whereas it had infected the quality of tobacco raw material because of the unscientific applying dosage,it is significant for us to find a scientific and reasonable fumigant dosage to control these pests. The fumigant activities of three organophosphorus insecticides such as dichlorvos,chlorpyrifos and phoxim against 3 rd larva of Ephestia elutella( Hubner) were tested under the closed flask holding oils indoors at dosage of 3,6 and 9 g /m3 correspondingly. The results showed that of the three insecticides,the control effects of dichlorvos were best,followed by phoxim and chlorpyrifos. The corrected mortality of pest treated with dichlorvos at 3 g /m3 was up to 89. 9% after 3 days,which treated with phoxim at 6 g /m3 was up to 88. 3%after 5 days,and the corrected mortality of pest treated with chlorpyrifos at 6 g /m3 was up to 76. 3% after 5 days.The dichlorvos is still an ideal fumigant drug for controlling Ephestia elutella( Hubner) pest in farm storehouse of China at present.