Vegetables are important as a world food source. There is no accurate estimate of their total contributions since they generally do not play an important part in international trade. There is usually a very short time between production, marketing, and consumption. Their importance is greater than the area under which they are cultivated since intensified agriculture characterizes most production practices. Much of the culture is labor intensive and small scale. Vegetables are generally high value crops. Pesticides, fertilizers, and irrigation play an important role in their successful culture. Use of large amounts of these inputs is the general rule.