st.statistics - statistical analysis between 3 groups of data - what is the approptiate post hoc test for them?

I measured one dependent variable between three groups of data (control, group1, group2).The result of t-test indicates significant difference between control and group 1 (p vale =.04), control and group 2(p value .01), but not significant between group 2 and group 3.Do I still need to use the post hoc test? If so, which test is the most appropriate?