Which of the following nematodes specifically targets insects?

Certain species of nematodes are specifically known for targeting insects and are often utilized in biological control strategies. These nematodes, particularly the entomopathogenic nematodes, are parasitic and enter their insect hosts, ultimately leading to the insect's death. They release symbiotic bacteria that help in the digestion of the host's tissues, allowing the nematodes to feed and reproduce within the insect.

Commercially available insect-targeting nematodes, such as those from the genera Steinernema and Heterorhabditis, are widely used in Integrated Pest Management (IPM) programs because they provide an environmentally friendly alternative to chemical pesticides. They effectively manage pest populations while posing minimal risk to beneficial organisms and humans.

In contrast, not all nematodes have this insect-targeting capability. Many nematodes are either free-living in soil or specifically attack agricultural crops' roots. Some nematodes can be harmful to humans, but these do not fall under the category of insect-targeting nematodes. Therefore, the distinction is critical in IPM practices where specific biology is utilized for pest control.