ABSTRACT
Nematodes, unsegmented roundworms, are among the most abundant creatures on earth, representing 80 to 90 percent of all animals (Boucher and Lambshead, 1994; Blaxter et al., 1998). Nematodes probably establish parasitic relationships with all other complex animals and plants (Blaxter and Bird, 1997). Plant-parasitic nematodes are serious crop pests, causing an average yield loss of 12.3 percent annually, and as high as 20 percent in crops such as banana (Sasser and Freckman, 1987; Koening et al., 1999). In monetary terms, the crop loss is over U.S. $100 billion annually worldwide. In addition to direct crop loss, the control of nematodes requires the use of nematicides in many circumstances, costing a large amount of money and causing environmental pollution. For example, over 49,000 metric tons of nematicidal active ingredient was applied to crops in the United States alone at a cost exceeding U.S. $1 billion in 1982 (Landels, 1989).
