Fumigation activity of Frankliniella occidentalis, western flower thrips, and phytotoxicity were evaluated with phosphine(PH3) and ethyl formate (EF) in the asparagus. Fumigation activity of PH3 and EF showed in the order of egg (64.7 mg·h/Land 132.9 mg·h/L), nymph (5.5 mg·h/L and 14.8 mg·h/L), and adult (3.8 mg·h/L and 14.7 mg·h/L) respectively at 5˚C in12 L desiccator. The adsorption of PH3 was 24% at 5˚C. However, the adsorption of EF increased sharply to 98% at 5˚C.PH3 showed 100% control for all development stage of F. occidentalis with 4g/m3 in 0.65m3 at 2˚C for 48h exposure. Thephytotoxicity was not found. The results revealed that the EF is highly absorbable in asparagus, so it is not suitable as afumigant, but PH3 is considered to be suitable as an alternative MB fumigant for control of the F. occidentalis in asparagus.