This audiotutorial unit (cassette, printed script, 70 color slides, study guide, self-evaluation test), prepared by the Communications Support Unit at CIAT, is available for use with a manually or automatically synchronized slide projector/cassette tape recorder. Each unit is available from the Distribution Office at a cost of US$ 50; photocopies of the study guide alone can be obtained from the Cassava Information Center. Data are given on the biology of the hornworm, its economic importance and possible methods of control.

A description is given of the different factors limiting to bean production in Latin America, type of damage caused, environmental conditions where they prevail, and possible control measures. With regard to diseases, the following are discussed: aphid-, whitefly- and beetle-transmitted viruses, foliage- and pod- infecting fungi, root- and stem-infecting fungi, bacterial diseases, nematodes and seed pathology. Insect pests are grouped according to the part of the plant attacked: seedlings, leaves, pods and the stored seeds.

Se discuten varios conceptos relativos al mejoramiento de leguminosas forrajeras y a su adaptacion a suelos acidos de baja fertilidad. Se observa que es raro que un ecotipo nativo selecionado ofrezca todas las caracteristicas requeridas para praderas de pastoreo. Los objetivos del mejoramiento deben ser muy especificos, lo cual se logra con una estrecha colaboracion entre los introduccionistas de plantas, agronomos especialistas en leguminosas y cientificos en la utilizacion de pasturas.