Sampled <i>Pinus</i> spp. from different geographical areas and classified based on the PWD symptoms they expressed. +, presence of nematode; -, absence of nematode.

a0 – tree without symptoms, I - <10% brown leaves, II - 10–50% brown leaves, III – 50–80% brown leaves, IV - >80% brown leaves, V- dead tree without leaves. bA- Aphelenchoidae and R- Rhabditidae