Fungicides and Mycorrhizae

[FaganJohns]

Most fungicides that are used to treat garden plants do not go far into
the soil.  It takes a pretty powerful and soluble fungicide to get through
all those soil particles to get to the micorrhizae.  Unless you are using
one that is designed to kill root fungus diseases, I wouldn't worry about
it.  Fungicides like "Captan" and others that are designed to keep fungus
off fruits and vegetables may stunt them a little, but it is not a big
problem.