The fungus powder can only make the opposite sex attracted to each other through second hand exposure. However, as seen with the girl on girl scene in the locker room, if two of the same gender inhale the powder, they go for the first living body they see.

The fungus was previously shown to be sentient, explaining how it knows how much powder to expel. Explaining how it only used two shots to incapacitate the landlady, while releasing a endless stream at the militarily base.

When the landlady is sprayed by the fungus, it's second shot is purposely aimed at her crotch. Notably this is where she rubs the most when the arousal kicks in; suggesting the powder can increase sensitivity.