But the principal culprit is Cryphonectria parasitica, the fungus that causes chestnut blight.

但栗疫病菌才是罪魁祸首，是这种真菌致栗树感染了栗疫病 。

In the late 19th century, some infected saplings from Asia brought C. parasitica to North America.

19世纪后期，一批亚洲来的感染栗疫病菌的树苗把C寄生菌带到了北美。

Since C. parasitica is Asian, Asiatic trees have evolved resistance to it.

由于C.栗疫病菌源于亚洲，亚洲树种已经进化出对该真菌的抗性。

Dr Powell knew that many of the symptoms of chestnut blight are caused by the oxalic acid that C. parasitica generates as it grows.

鲍威尔知道，栗疫病的很多症状都由栗疫病菌生长时产生的草酸引起。