Non-infectious DiseasesNon-infectious diseases are caused by abiotic or non-living agents. Temperature and moisture extremes, chemical and fire injuries,nutrient abnormalities, air and water pollution, etc. are well known abiotic agents causing disorders. Non-infectious diseases are recognized by their uniform expression and the lack of progressive symptom development.
In bamboos, severe damage caused by glazed frost has been reported from China and Taiwan-China (Anonymous 1979; Qju 1982; Zhou 1988). During 1988, about 380O ha of Phyllostarhys pubescens stands in Qianshan County of Anhui Province, China, were severely affected by glazed frost (Zhou 1989; Tao 1990). An economic loss of 9 million renminbi yuan has been reported from the damage caused to bamboo stands. Other species of bamboos were also affected. The seriousness of the disaster was related to gradient and altitude of stand sites, and also to the stand density. The extend of glazed frost damage decreased with increase in stand density.
Young bamboo stands are severely affected by the frost. Foliage and young shoots are gravely injured during the winter, and injured shoots and foliage become susceptible to fungal pathogens (Figs. 13O, 131 ).Weighing down by snow also reduces bamboo yield and affects culm quality. Silvicultural measures suggested to reduce glazed frost damage include: increasing the density in the groves; application of silica fertilizer to improve the hardness and elasticity of bamboo tissues; raising mixed stands of broad-leaved trees and bamboos; regulating the stand structure by rational harvest; removal of the small and weak bamboos; and planting cold-resistant bamboos (Zhou 1989; Tao 1990).
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Fig. 130: Frost
damage in Indosasa sp. at Nanjing, China
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