This manual gives information on insects that damage crops. These fall in two categories: (1) insects with a complete life cycle such as butterflies and moths, boring insects, and beetles; and (2) those with a gradual life cycle. Also included are descriptions of leaf diseases, wilts and root and crown rots, stem cankers, fruit rots, seed and seedling diseases, smut disease, viruses and mycoplasmas, nematode diseases, and weeds. Finally, a brief explanation is given of the classes and uses of pesticides. (BB)