[Agroforestry] forest tree diseases

[fuskay]

hi ;
i need information about the important forest tree diseases world
wild... what is the most important disease nowadays ..... what is the
fist steep for a survey ... for example i want to study phytophythora
diseases in native or plantation forests what must i do? there may be
lots of questions like this i am waiting for your advices...
thanks a lot ..
funda oskay:)