Environmental and public health problems arising from the use of chemical insecticides have led to an increasing demand for alternatives for insect pest control. Together with this, widespread public concern resulting in governmental bans on many of the most effective insecticides and development of insecticide resistance has severely reduced the range of useful insecticides available. Alternative control measures such as the biological control of pest insects with parasitoids and predators and microbial biocides have been in field use for several decades. Although these alternatives are being continually improved, most insect pests are nonetheless still controlled with chemical insecticides. This book presents the latest work on the biological control of insects using nematodes; it covers a range of topics that will help provide a better understanding of the potential problems involved in developing these nematodes as biological control agents. Nematodes infect hundreds of different species from most orders of insects and affect their insect hosts in a variety of ways.