All the genera of virus-vector nematodes belong to the order…

✅Explanation:
All known genera of plant-parasitic nematodes capable of transmitting viruses belong to the order Dorylaimida. These nematodes are ectoparasites, meaning they feed on the outside of plant roots without entering them.

• Two major families within the Dorylaimida order are known to transmit plant viruses:
Longidoridae: Genera within this family, such as Longidorus (needle nematodes) and Xiphinema (dagger nematodes), transmit various plant viruses, including nepoviruses and tobraviruses.
Trichodoridae: This family includes the genus Trichodorus (stubby root nematodes), which are known to transmit tobraviruses.

🔑Key Points:
(a) Tylenchida: This order includes many important plant-parasitic nematodes, such as root-knot nematodes (Meloidogyne) and cyst nematodes (Heterodera).
(d) Xenorhabditida: This order includes a diverse group of nematodes, including both free-living and parasitic species.