Abstract: A hermetically-sealed fumigant container having a can enclosing a smoke-generating mixture and an internal heater formed of auto-combustible material for activating the mixture to produce an exothermic reaction resulting in smoke which disperses pesticidal agents into the atmosphere of the area being fumigated. The mixture preferably has an ammonium nitrate and dicyandiamide base and a silica additive which acts to regulate the exothermic reaction whereby the reaction proceeds at a substantially constant rate.