California drought has killed all of the Ponderosa Pines, Cedars, & Douglas firs. Now I'm losing Live Oaks and the Juniper to root rot. These are mature trees that are just falling over, the Juniper looked very healthy just before it toppled. The soil is full of white hairy threads. Afghan Pine seedlings have died near the Juniper. How can I replant if the soil is infected? Is there a recommended fungicide that can be used on soil and large areas.