Fear of mushrooms is called mycophobia, and the fear of snails is molluscophobia.
I myself suffer (now to a mild degree) from nyctophobia (darkness), aquafobia (waterfright) (although only open water like at the beach, pools are no problem), and I think it might just be scyphophobia (fear of jellyfish), acrophobia (heights), agoraphobia (open areas, but restricted to open areas with buildings. Nature is fine) and anthropophobia (too many people).
I have been battling the different phobias since childhood, but seem to be at a point now where I just get a bit nervous and edgy when they strike.
It seems you have to face your fear, and take it in small doses. Then increase the dosage over time. The exception here is thanatophobia (fear of death) - that's requires a different approach