Abstract: The present invention relates to a method of fumigation and detoxification of plant seed and to an pneumatic apparatus having a positive pressure air source, seed feed, a vacuum wheel air lock, fumigant and detoxicant source, a spraying apparatus for introducing the fumigant and/or the detoxicant and an exit cyclone having an optional air return for returning fumigant and/or detoxicant saturated air to the apparatus. The inventive apparatus and method have been found effective for aflatoxin B.sub.1 and B.sub.2 suppression as well as for insect extermination in infested plant seed.