where are you..

what trees..

how educated are you .. should we simply rely on your diagnosis ..???

and.. finally.. healthy trees dont rot.. so why are they rotting...

one might argue.. that ROT.. is not a disease.. but a by product of some other endemic problem ...

i dont want to see us go off on a discussion.. if that might not actually be the problem ...

ken

Can you identify the disease as to its Latin name? And how did you come to determine this was the problem? "brown root rot" is a common name for Phellinus noxius, a pan-tropical/subtropical pathogen.......not a likely issue to be present in a northern hemisphere garden. But then we don't know exactly where you are located, either :-))

There are various other root rots - many, in fact. While some of them are the result of pathogenic organisms living in the soil, just as many (or more) are the result of excess moisture or poor drainage. 'Dealing' with a root rot is less a matter of treatment (there typically aren't many) than it is adjusting the cultural conditions or selecting a resistant species.

But it is essential to get an accurate diagnosis for your problem before any sort of suggestions to accommodate it can be made.