Which genus of beneficial nematodes is commonly used against soil-dwelling pests?

• A. Steinernema
• B. Heterorhabditis
• C. Necator
• D. Pochonia

Answer: (A)

Beneficial nematodes used against pests in the soil are entomopathogenic, meaning they infect and kill insect larvae living underground. Among the genera used for this purpose, Steinernema is the most commonly applied in practice. These nematodes pair with symbiotic bacteria that hitch rides inside the host; when a Steinernema finds a suitable pest, it enters through natural openings, releases its bacteria, and the host dies within a day or two. The nematodes then reproduce inside the dead insect and emerge to seek new hosts, creating a reliable cycle for controlling soil-dwelling larvae and grubs. Steinernema species are well-represented in commercial biocontrol products and can be applied with standard irrigation or spraying methods, making them a practical choice for farmers and landscapers.

Heterorhabditis is also used for soil pests, but the question highlights Steinernema as the widely referenced genus in this context. Necator refers to parasitic organisms not used for soil pest biocontrol, and Pochonia is not a nematode genus used for this purpose.