Herbs for Athlete's Foot and Jock Itch

What would be a good herb to add to glycerin base soap to combat athlete's foot and jock itch?

Athlete's foot and jock itch, both fungal infections that may be compounded by bacterial infection with scratching, would benefit by the addition of tea tree (antifungal), calendula (antifungal and skin healing), lavender (antimicrobial and healing), thyme (antifungal and antibacterial) and comfrey (soothing and skin healing). If you are using tea tree or thyme essential oils, be very careful with the amount used. They both irritate the skin, so must be diluted many times.