With intensive use of DDT, tropical diseases were greatly reduced during the fifties, but not eradicated; in fact, they have come back again--with the vector insects having developed an increased multiple resistance to most chemical insecticides. The high doses of chemicals have caused a deep contamination of the environment, dangerous both to man and animals. The use of environment-friendly materials for vector control is now essential and has initiated an intensive search for new biological factors that will support or replace some chemical treatments. Based on the Collaborating Center's many years of experience in vector pathology, it will help field workers with different aspects of field handling of interesting new pathogens and parasites, serving as a field guide for an intensive search for new and effective organisms. Sections discuss: transportation, storage and evaluation of field materials; characterization of pathogens; parasitoids and predators of vectors and more.
