Cassava is a low-priority crop in agricultural development policies in most L.A. countries, limiting active research and extension activities. A description is given of CIAT-generated low- cost technology that can increase yields. This package consists of the visual selection of planting material; chemical treatment (fungicides + insecticides + micronutrients) of the selected cuttings; proper preparation of the cuttings (cut rectangularly at 20 cm, with 5-7 nodes) and planting vertically at a depth of 10 cm; and the use of high-yielding, adapted var. Cassava should be planted on ridges when soils are heavy textured with greater than 1200 mm rainfall/yr. On Oxisols and Vertisols, cassava should be fertilized with 1/2 t dolomitic lime and 1 t/ha 10-20-20NPK + 20S + 10Zn. In other soils, sufficient fertilizer to replace the nutrients extracted in the final product should be applied. Timely control of weeds is important. Pest-tolerant var. should be used; rotation or fallowing can also be practiced to break pest cycles. If disease-resistant material is not available, planting should be timed to avoid disease attack. Mechanical harvesting aids and storage of fresh roots are also discussed. (AS)

Bean production trends during the years of 1947-51 and 1973-77 were analyzed for the different states of Brazil and some marketing policies for surplus crops are suggested. The state of Parana was the largest producer during 1947-51 and 1973-77 with 203,506 and 561,360 t, resp., representing 20.7 and 31.5 percent of the total national production. Bean yields decreased during the period 1973- 77 with values ranging between 2.6 percent for Sao Paulo and 55.4 percent for Ceara. Bean production decreased with the introduction of other crops such as cotton and soybean, host plants of the whitefly (Bemisia tabaci), vector of BGMV, and therefore competing for area dedicated to bean production. Prices vary widely, especially for some var. due to consumer preferences. Suggestions include policies of bean storage to eliminate seasonal variation in price and protect both the consumer and the producer, development of disease-resistant var., and survey of consumer preferences of bean var. Tables and figures are included for analyzing the observed trends. (CIAT)