Abstract: 【Aim】Lema decempunctata is a significant pest with chewing mouthparts that affects the organic cultivation of Lycium barbarum. This pest frequently feeds with Aphis gossypii, thereby complicating control efforts. The purpose of this study is to investigate the impact of A. gossypii infestation on the growth and development of L. decempunctata, reveal the disaster mechanism of L. decempunctata and provide the guidance for the pest prevention and control.【Methods】The impacts of individual and combined infestation of the 3rd instar nymphs of A. gossypii and the 2nd instar larvae of L. decempunctata on L. barbarum plants, on the larval duration of L. decempunctata, as well as on the body length, body width body weight, and head width of the 3rd instar mature larvae and adults of L. decempunctata were investigated. Additionally, the effects of these infestation on the feeding selection rate of larvae and the oviposition rate of adults of L. decempunctata, along with on the contents of salicylic acid (SA) and jasmonic acid (JA) in  the leaves of L. barbarum, were examined.【Results】When A. gossypii infested L. barbarum plants alone, the total larval duration of L. decempunctata was significantly reduced by 11.68%， the body width of the 3rd instar mature larvae of L. decempunctata was increased by 13.67%, and the body weight, body width and head width of L. decempunctata adults were significantly increased by 30.68%, 32.64% and 32.90%, respectively, as compared to those in the control (healthy plants without pest infestation). When L. decempunctata larvae infested L. barbarum plants alone, the total larval duration of L. decempunctata was 12.04% longer than that of the control, however, no significant differences were observed in the body weight, body length, body width and head width of either the larvae or the adults of L. decempunctata between the treatment group and the control group. When A. gossypii and L. decempunctata infested L. barbarum plants together, the body weight, body length, body width and head width of either the larvae or the adults of L. decempunctata showed no significant differences from those in the control. Regarding the selection behavior, compared to the control, the larval feeding and adult oviposition of L. decempunctata first preferred to the L. barbarum plants infested with A. gossypii alone, and then to the L. barbarum plants infested with A. gossypii and L. decempunctata together. A. gossypii infestation resulted in a notable increase in SA content in the leaves of L. barbarum, while had no significant effect on the JA content in the leaves of L. barbarum compared with the control. In contrast, L. decempunctata infestation led to a significant increase in the JA content in the leaves of L. barbarum, while caused no significant impact on the SA content in the leaves of L. barbarum compared with the control.【Conclusion】A. gossypii infestation could significantly elevate the SA content in the leaves of L. barbarum, inhibit the accumulation of JA in the leaves of L. barbarum, promote the growth and development of the larvae and adults of L. decempunctata, and enhance the feeding and reproductive activities of L. decempunctata. However, this promoting effect was mitigated in the presence of L. decempunctata.

Key words:  Lema decempunctata, Aphis gossypii, Lycium barbarum, interspecific relationship, plant hormone