In which method is steam used as a phytosanitary treatment?

Steam is utilized in phytosanitary treatments primarily to kill pests present in soil or plant materials. This method, known as steam sterilization, involves exposing the soil or the plant material to steam at specific temperatures and durations, effectively eradicating harmful organisms such as insects, nematodes, and certain pathogens that may threaten plant health and agricultural productivity.

The use of steam for this purpose is advantageous because it can penetrate deeply into the soil, ensuring that even pests located below the surface are effectively killed. This method is environmentally friendly, as it avoids chemical treatments that could have adverse effects on the surrounding ecosystem. Moreover, steam sterilization reduces the risk of regrowth of pests compared with other treatments since it effectively targets a wide range of microorganisms.

In contrast, the other methods mentioned in the choices do not align with the specific use of steam for pest control. Enhancing soil fertility, promoting plant growth, and conserving moisture pertain more to practices aimed at improving plant health and productivity rather than directly addressing the elimination of pests through steam application.