What fumigant is primarily used for treating bulk-stored grain?

Aluminum Phosphide is primarily used for treating bulk-stored grain due to its effectiveness as a solid fumigant that releases phosphine gas when it comes into contact with moisture. Phosphine penetrates grain structures effectively, providing control over a wide range of stored product pests, including insects and rodents. This fumigant is favored in the grain industry because it not only acts rapidly but also has a relatively low application rate and minimal residue following treatment, making it suitable for use in food storage environments.

Other fumigants listed may have applications in pest control but are not primarily used for treating bulk-stored grain. Ethylene Oxide is generally utilized for sterilizing medical equipment and in some cases for fumigating food products, but not specifically for grain. Methyl Bromide, while historically significant in agriculture, has seen restrictions due to its ozone-depleting properties and is not typically used for grain fumigation anymore. Sulfuryl Fluoride, although effective for structural fumigation and various pests, is not the go-to choice for the specific needs of bulk grain storage. Thus, Aluminum Phosphide stands out as the fumigant of choice for this application.