Nematodes are exceedingly small round worms. These pine wood nematodes were extracted out of pine wood from a dead tree.
Higher magnification of pine wood nematode Bursaphelenchus xylophilus.
Long horned beetles like these Monochamas species are vectors of the pine wood nematode.
Beetles maturation feed on small diameter pine branches. Nematodes that are carried by the beetle enter the wounds.
After feeding, female beetles make oviposition niches on the bark and lay an egg in the niche. Black circles show the oviposition niches. Nematodes can also move into the wood when niches are made and eggs laid.
Larvae of the beetle. The larvae feed on the wood and just before pupation nematodes in the wood move up into the developing beetle. As the beetle emerges, it carries nematodes with it.