Plant quarantine is vital to prevent the introduction of non-indigenous, potentially damaging pests and diseases of plants into a country or to eradicate them before they can become widespread and well established. Less-developed countries and other countries in transition are especially vulnerable to the damaging effects of exotic pest introductions because of often inadequate infrastructure and the fragility of their economies. The well-meaning importation of germplasm for agricultural development projects creates a further risk of introducing such quarantine pests. Without stronger phytosanitary services nations will be unable to participate in the liberalization of world markets.