Abstract: 【Objective】The objective of this study is to establish a rapid and efficient method for testing the sensitivity of      B. cinerea to fungicides by using the enzyme-labelling measuring instrument. 【Method】With △OD value as an evaluation index, the conditions of microtiter method to test the sensitivity of B. cinerea to fungicides were optimized. The effect of six widely-used fungicides (boscalid, azoxystrobin, diethofencarb, thiophanate-methyl, iprodione and difenoconazole) against B. cinerea spore germination and mycelial growth was tested, and the results were compared with the conclusions of spore germination method and mycelium growth rate method.【Result】The conditions of microtiter method were optimized. The determination wavelength was 630 nm, the medium was PDE, the concentration of conidial suspension was 8×105-1.6×106 spores/mL, the optimum culture conditions were under shaking culture (150 r/min) at 21℃ in the dark, the text time for the inhibition of spore germination was 24 h after adding fungicide and conidial suspension in the wells, and the testing time for the inhibition of mycelial growth was 12-24 h after adding fungicide (conidial suspension in wells was incubated for 12 h before adding fungicide). The conclusion was almost consistent with that from conventional spore germination method or mycelium growth rate method. Fifty-seven isolates of B. cinerea from three regions of Shandong Province were tested by this method, and the mean EC50 values were 1.9311 and 5.6488 μg•mL-1 for inhibition of conidial germination and mycelial growth, respectively.【Conclusion】Microtiter method combines the advantages of both conventional methods together, it has characteristics of fast testing speed, high measuring accuracy and good reproducibility, so it possesses better practicability.

Key words: microtiter method, Botrytis cinerea, sensitivity, testing conditions