英语语法分析

In fact, the psyllid eats knotweed exclusively.

事实上，虎杖虱只吃这一种植物。

But the potato psyllid is merely the vector. The actual pathogen is still elusive.

但马铃薯木虱只是传播媒介，真正的病原体尚不清楚。

It appears to be related to a bacterium transmitted by the potato psyllid's relative, the citrus psyllid.

该细菌似乎和马铃薯木虱的亲缘生物——柑桔木虱——传播的细菌有亲缘关系。