Why is quarantine necessary?
At both the national and international level, there are glaring examples of enormous losses caused by the pests and diseases introduced with import of agricultural commodities. There are glaring examples of entry of pests* into new areas along with introduced planting material. The introduction of the late blight pathogen (Phytophthora infestans) of potato into Europe from Central America in the middle of 19th century, powdery mildew (Uncinula necator), root eating aphid (Phylloxera vitifolia) and downy mildew (Plasmopara viticola) of grapes into France in quick successions also in mid 19th century from America, chestnut blight (Endothia parasitica) into USA on the nursery stocks imported from the Orient in 1904 and coffee rust (Hemileia vastatrix) into Sri Lanka in 1875 are some of the well authenticated examples of international spread of important plant diseases. All these introduced pests are causing enormous loss to human health, environment and biodiversity besides direct loss to
