What's the best way to get rid of mealy bugs eating my tomato plants?

Those white, sticky mealy bugs are eating my tomato plants and have also attacked the olive tree right next to them. The leaves of the tomato plants are wilted, curled and brown on the ends. What's the best way to get rid of the mealy bugs? Should I buy pesticides? If so, what kind? Should I buy some other insects to eat the mealy bugs? Please help! Thank you.