ABSTRACT
Plant density is affected by many practices such as spacing, pruning, thinning, fertilization, water management, staking, trellising, and harvesting plants or plant parts. The proper distance of planting has been a concern of farmers for centuries. Staking and pruning were used by traditional farmers to alter the architecture, and thus the crop density, of beans in East Africa. Free water is necessary for the germination and penetration of many fungal spores, and dense stands allow free water to remain on plant parts for longer periods than in widely spaced stands. In closely packed plants the microenvironment changes; temperatures become more uniform, relative humidity increases, and leaves stay wet longer after rain or dew. Adequate aeration is important in the prevention of many diseases, and good crop ventilation is enhanced by sowing or planting in rows parallel to the direction of prevailing winds. Avoiding foliage or root contact can reduce the incidence of some diseases.
