Grooming and sartorial choices
Because pubic hair traps moisture, an especially bushy bush can contribute to your odor problem. Trimming the hair can help, though the decision to do so is a pretty personal one that no one should feel is being dictated to them.
If you do choose to clip your pubes, a beard trimmer outfitted with a beard attachment will allow you to easily zip through the area without having to worry about taking too much off or, yikes, nicking something.
Underwear can play a big role in the development of ball sweat, so you may want to try a new style if you're really having a problem down under. Choose a material that breathes well, like cotton, and a style that is neither too loose nor too restrictive (boxer briefs get high marks).
One last thing
If, after adopting a more thorough washing and drying routine, using an absorbent powder and switching to a different style of undergarment, you're still experiencing a problem with testicular odor, go see a doctor. There's probably nothing major wrong with you, but you may have developed a fungal infection and you should get that checked out.
Fungal infections, despite how gnarly they sound, can be treated quite easily, so go get it dealt with. Your balls will thank you.