Information on some diseases and pests that attack cassava, as well as the symptoms induced by nutritional deficiencies and toxicities and damage resulting from the misuse of herbicides are given in this manual. Specific and general recommendations regarding the control of the described problems are included. Disease control on a commercial scale is discussed. Formulae suggested for stake treatment before planting and storage and a key for identifying some cassava diseases are annexed. Color photos on symtomatology are included. (AS)

Numbers of plant species and individuals were examined relative to land use in an agricultural settlement in the Brasilian Amazon. Land uses were forest, cropped after forest, fallows, cropped after fallow, and pasture. These uses corresponded roughly to farmers` land use changes over time. As expected, species diversity was high in forest. Diversity was also high, however, in fallows of 3-5 years--as a result of both survival/reestablishment of forest species and appearance of plants not found in forest.