Abstract: 【Aim】 To find effective attractant formulations for trapping Holotrichia oblita for ecological prevention and control. 【Methods】 Five plant volatiles, two aggregation pheromones and one sex pheromone were selected. According to the optimal concentration of each chemical, these compounds were mixed in pairs. A total of 17 binary attractant formulations were obtained, including plant volatiles plus aggregation pheromones, plant volatiles plus sex pheromones and aggregation pheromones plus sex pheromones. Based on the electro-antennogram (EAG) and taxis, the formulations with high attractiveness to H. oblita adults were gradually screened. Then, the trapping efficacies of these formulations and their single components on H. oblita adults were compared, and the attractiveness of these formulations was tested by trapping test in the indoor cage. 【Results】 Three binary attractant formulations cis-3-hexenyl acetate+(Z)-9-octadecene acetate, 1-hexanol+(Z)-9-octadecene acetate, and dibutyl phthalate+methyl glycate with strong attractiveness to H. oblita adults were screened from 17 attractant formulations by EAG and taxis tests, causing the EAG responses of 5 981%, 5 796% and 5 722%, respectively, in females, and 3 983%, 4 712% and 3 809%, respectively, in males. The formulation dibutyl phthalate+methyl glycate caused the highest selective response rate (71.21%) in H. oblita adults, followed by the formulations 1-hexanol+(Z)-9-octadecene acetate and cis-3-hexenyl acetate+(Z)-9-octadecene acetate (70.84% and 70.72%, respectively), causing significantly higher selective response rate than other formulations. The results of comparison of attractiveness between three formulations and their single components showed that the formulation cis-3-hexenyl acetate+(Z)-9-octadecene acetate showed significant synergistic effect on cis-3-hexenyl acetate but showed no significant synergistic effect on cis-9-octadecyl acetate. Both the formulations 1-hexanol+(Z)-9-octadecene acetate and dibutyl phthalate+methyl glycate showed significant synergistic effect on their respective single components. The results of indoor caged trapping showed that the numbers of adults trapped by the formulations cis-3-hexenyl acetate+(Z)-9-octadecene acetate, 1-hexanol+(Z)-9-octadecene acetate and dibutyl phthalate+methyl glycate were significantly higher than that of the control (paraffine oil). The formulation cis-3-hexenyl acetate+(Z)-9-octadecene acetate caused the highest selective response rate (74.06%) in H. oblita adults, while the formulations 1-hexanol+(Z)-9-octadecene acetate and dibutyl phthalate+methyl glycate caused the selective response rates of 65.89% and 64.25%, respectively. The selective response rates in H. oblita adults caused by the three formulations, however, showed no significant difference. 【Conclusion】 The binary attractant formulations cis-3-hexenyl acetate+(Z)-9-octadecene acetate, 1-hexanol+(Z)-9-octadecene acetate, and dibutyl phthalate+methyl glycate show strong attractiveness to H. oblita adults and can be used as effective attractants to ecologically control this insect.

Key words: Holotrichia oblita; plant volatiles, pheromone, binary formulation, trapping efficacy, taxis, selective response rate