Abstract
This chapter outlines the historical records of insect nematology before highlighting the major groups of beneficial nematodes. These include entomopathogenic nematodes to use against insect pests, slug nematodes to manage mollusc pests, entomophilic nematodes such as Thripinema to manage thrips, predatory nematodes to manage plant parasitic nematodes and fungal-feeding nematodes to manage soilborne plant pathogens. Research achievements related to these nematode groups, particularly in managing insect pests, mollusc pests and plant pathogens, are summarized. Major impediments that preclude beneficial nematodes from a significant share of the pesticide market are presented, and possible solutions for their effective utilization are discussed. To develop these nematodes as biopesticides, only those nematode groups that will be financially beneficial to the biological control market and that have had promising results published will be addressed. Future research priorities and goals are also identified.