Abstract: 【Aim】 Eriosoma lanigerum, Aphis citricola and Stephanitis nashi are important insect pests in apple orchards, and cause different degrees of damages to apple trees by piercing-sucking mouthparts. This study aims to explore the differences of feeding behaviors of the three piercing-sucking insects on apple tree. 【Methods】 The EPG parameters of E. lanigerum and A. citricola  adults in the phloem and non-phloem of apple seedlings and the feeding behaviors of E. lanigerum, A.citricola and S. nashi adults on apple seedlings were compared by using the electrical penetration graph (EPG) technique. At the same time, the proportions of the average duration of various waveforms of the adults of the three pests feeding on apple seedlings for 8 h were also analyzed. 【Results】 There are six types of sucking waveforms produced by E. lanigerum and A. citricola adults on apple seedlings, i.e., the non-penetration (np) wave, stylet pathway phase wave (C), intracellular feeding wave (pd), xylem feeding wave (G), release of saliva into the phloem wave (E1) and ingestion from phloem wave (E2), while there are four types of sucking waveforms produced by S. nashi adults, i.e., the non-penetration (np) wave, surface piercing wave (A), mesophyll cell feeding wave (Gc), and xylem feeding wave (E). According to the EPG parameters of aphids in the non-phloem of apple seedlings, the average duration of pd wave of E. lanigerum adults was significantly longer than that of A. citricola adults, but the count of probes, total time of np wave and count of pd waves of E. lanigerum adults were significantly lower than those of A. citricola adults. According to the EPG parameters of aphids in the phloem of apple seedlings, there was no significant difference in every parameter except the time from the first probe to the first E2. According to the proportions of duration of various waveforms of three pests feeding on apple seedlings, the proportion of the total time of np waves of S. nashi adults was the highest (53%), followed by that of A. citricola adults (24%), and that of E. lanigerum adults was the lowest (1%). At the same time, the feeding waves of E. lanigerum and A. citricola adults were E2 waves, which accounted for 35% and 25% of the total time, respectively, while those of S. nashi adults were Gc wave (accounting for 36% of the total time) and E wave (accounting for 11% of the total time).【Conclusion】 This study illustrates the mechanisms of niche separation and feeding behavior of pests with piercing-sucking mouthparts in apple orchards, providing a theoretical basis for the comprehensive management of pests with piercing-sucking mouthparts in orchards.

Key words: Eriosoma lanigerum, Aphis citricola, Stephanitis nashi; piercing-sucking insects, apple, feeding behavior, electrical penetration graph