The symptoms and characteristics of two virus and one fungus disease and four nutritional disorders of sugar beet which cause chlorosis and necrosis of the foliage are described. The causes of the diseases and methods of distinguishing between them have been investigated by analytical, pathological and field experimental methods.Experiments in which diagnosis was confirmed by serological and spectrochemical methods show that the two often easily confused diseases, sugar‐beet yellows virus and magnesium deficiency, can be visually distinguished.Sugar‐beet yellows virus reduces the potassium, but slightly increases the magnesium content of the leaves.Magnesium deficiency symptoms are associated with a low magnesium content of the foliage, but may be induced by salt applications without greatly affecting the magnesium analysis.‘Potash’ deficiency symptoms are often, but not necessarily, associated with a low potassium analysis and may actually be caused solely by a deficiency of sodium. In the field, symptoms are induced by sulphate of ammonia and phosphate applications and may be prevented in some cases by the application of either salt or muriate of potash, in others by salt only. Some interchangeability of the functions of potassium and sodium in the plant is suggested.Manganese deficiency symptoms are associated with a low manganese content of the leaves, which can be readily increased by spraying or injection with manganese sulphate solution, but a high concentration of manganese in the foliage, such as sometimes occurs naturally on acid soils, has a toxic effect.

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Mechanical properties of sugar beet are important during harvesting and processing. To potentially correlate mechanical properties with structural features of cell wall polymers, four different Beta varieties (Beta vulgaris L.) were characterized for their mechanical properties and cell wall composition. In addition, the influence of nitrogen fertilization was analyzed. Additional nitrogen fertilization only slightly influenced mechanical properties and cell wall composition. Hardly any structural differences of cell wall polysaccharides were observed for all Beta varieties. Slight differences in alcohol insoluble residue and protein contents, in amino acid profiles of proteins, and in esterification degree of pectins were found. The Beta varieties differed in their contents of cell wall bound phenolic components, and particularly in their dry matter contents. Analyses of mechanical properties of the Beta varieties demonstrated differences in tissue firmness and compressive strength. However, no evidence was found that the observed differences of cell wall composition are responsible for the divergent mechanical properties, with the exception of water contents that were higher in samples with less compressive strength.

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