Fumigation is also considered an effective method of chemical application in some fruits. It has several promising applications. Fumigation can be carried out immediately after harvest to prevent infection of injuries on the fruits to be transported to long distances, degreened before processing, or to be held for several days before processing. Sulfur dioxide (SO2) is mainly used as a fumigation agent for controlling postharvest diseases of Vitis venifera, that is, grapes. This is achieved by placing the boxes of fruits in a gas-tight room and the gas is introduced from a cylinder in appropriate concentrations. A fumigation treatment, which results in a residue of 5–18 ppm SO2 in the grapes is found to be sufficient to control decay of berries. Its toxicity to B. cinerea spores was found to be proportional to temperature over the range 0–30°C. Treatment of grape berries with 1.0% SO2 for 20 min has also been found to be equally effective (Ryall and Harvey, 1959). SO2 can be corrosive, especially to metals, because it combines with atmospheric moisture to form sulfurous acids. If applied in high concentration, it can even bleach the color of black grapes. Especially, sodium metabisulfite impregnated pads are available which can be packed into individual boxes of fruits for a slower release of sulfur dioxide. Acetaldehyde fumigation of Sultania grapes at 5000 ppm for 24 h has been shown to reduce decay of berries by 92% as compared to untreated fruits. It is noteworthy that with this concentration, neither residues of SO2 remain nor an off flavor is developed in the berries