The germination and infection of conidia of brown spot needle blight fungus (Lecanosticta acicola) on pine needles were observed under scanning electron microscope (SEM). Results showed that the conidia on the needles of Pinus massoniana, P. elliottii and P. thunbergii all germinated in the same way, and their germ tubes invaded into the needles through stomata, mostly 3-4 days after inoculation. Tests indicated that the peroxidase activity in needles of the resistant host P. Massoniana, increased rapidly 5...