Dagger nematode is

Answer: Option A

Dagger nematode is Xiphinema.
Nematodes of the genus Xiphinema, commonly called dagger nematodes, parasitize plants.
Dagger nematodes are ectoparasitic, which means that all stages, except eggs, attack, and feed on the roots of the host plants. The nematode inserts its long stylet deep into the root while the body remains outside the root, in the soil. The stylet punctures cell walls as it penetrates plant tissues.