Abstract: 【Objective】The object was to study resistance mechanism of 3 different wheat varieties to S. avenae. 【Method】Aphids feeding behavior had been ascertained used EPG technique. 【Results】When this aphids feeding onWw2730 seedlings, time to 1st duration probing late than Xiaoyan22 and Batis significantly, probing interrupt before 1st duration probing more than Xiaoyan22 and Batis significantly, 1st duration probing shorter than Xiaoyan22 and Batis significantly; Duration of pd II-1 on Ww2730 and Xiaoyan22 longer than Batis significantly; Duration of pd in C wave on Ww2730 longer than Xiaoyan22 and Batis significantly; Times and duration of G wave (ingestion in xylem) on Ww2730 more and longer than Xiaoyan22 and Batis significantly; Times of spot G wave on Batis more than Ww2730 significantly, but duration of spot G shorter than Xiaoyan22 and Batis significantly; All time and Max duration of E1 fractions, and time of E1 fractions than following E2 wave period on Xiaoyan22 and Batis were all longer than Ww2730 significantly; there are no different of mean duration of 1st E1 wave on 3 varieties, but other E1 wave mean duration on Ww2730 and Xiaoyan22 shorter than Batis significantly; the other wave parameters, include times and duration of F and E2 were all no different on 3 wheat varieties.【Conclusion】Resistance mechanism of Ww2730 seelding to S. avenae is repress factor to S. avenae feeding in epidermis, thicker cell wall in mesophyll and has secondary metabolites in phloem. Resistance mechanism of Xiaoyan22 seelding to S. avenae is thicker cell wall and more cell layer in mesophyll. The feeding strategy of S. avenae against resistance of ww2730 is shorten second duration of secrete watery salivation to xylem than first.

Key words: Wheat, Sitobion avenae, Resistance mechanism, EPG, Feeding behavior