ABSTRACT
This chapter describes Allium white rot in detail because it provides an example of features common to other soilborne root diseases. Root diseases are a major source of loss in Allium crops throughout the world. The causal fungal pathogens have several features in common with each other. Also, the methods of dissemination are similar: most root diseases can be carried in vegetative planting material, or by any action which moves soil containing the pathogen. Plants can become infected at any stage of growth providing environmental conditions are favorable. However, the type of symptom and its severity are dependent on the growth stage of the host at infection and the duration of soil conditions favoring the pathogen. Control might be achieved by eradicating sclerotia in soil before planting or by applying treatments which protect the growing plant. Smudge is mostly confined to the dried wrapper scales of white-skinned cultivars.
