The pumpkin fruit fly(Zeugodacus tau) is a major pest of melon vegetables in temperate regions, and clarifying its dispersal patterns among mixed vegetable gardens and scientifically evaluating and screening trapping products are key to achieving green prevention and control. A systematic survey was conducted on mixed vegetable gardens in Wangcheng District, Changsha City, during the period of occurrence of Z. tau in 2023. The population densities of female and male adults on major host crops, as well as the rates of host fruit damage, were monitored, and their correlations were analyzed using linear regression models. At the peak fruiting stage of luffa(loofah), six types of lure-and-kill products were used to trap adult insects. The trapping efficacy was evaluated using one-way ANOVA, and the cost-effectiveness ratios were quantitatively analyzed. The results showed that Z. tau experienced two distinct directional dispersal events during the survey period. The overwintering adults aggregated on cowpeas, a non-host crop around pumpkin fields. They gradually migrated from cowpea fields to colonize pumpkin fields from mid-to-late May to early June. As the growth of pumpkin plants declined while luffa and bitter gourd grew vigorously, the adults dispersed directionally from pumpkin fields to luffa and bitter gourd fields in mid-to-late June. The results indicated that late May to early June and around June 24th were the critical time points for these two dispersal events, during which the population density of Z. tau underwent a reversal between the source habitat and colonized areas. First-generation adults developed in pumpkin fields began to emerge on July 4, and migrated to nearby sponge gourd fields to inhabit and feed. During the survey period, the fruit infestation rates of pumpkin, loofah, and bitter melon were significantly and linearly positively correlated with the female population density of Bactrocera tau. Moreover, the adjusted coefficient of determination(R2adj) was higher for females than for males. Among the six tested products, the dual-gender trapping product Wanyingmi insect viscose board(IVB) trapped the most female adults, with the highest female percentage and cost-effectiveness. For the male-targeted product Guodegang attractant adhesive(YZJ), it achieved the best trapping efficacy and cost-effectiveness.