烟草不同发育阶段对赤星病的抗性表现与综合防治技术

人工接种结果表明，随着烟叶自下而上逐渐成熟、衰老，抗病性下降。不同抗性类型的品种，其绿色叶片对病害均表现免疫或近免疫，近成熟叶片高抗，成熟衰老叶片表现为感病，与品种田间抗病性结果一致。田间结果表明，采用增施钾肥、适时打顶和下部叶片近成熟期摘除1～3片底脚叶等措施，提高烟草品种抗病性、配合有效的农药品种综合防治烟草赤星病，在重病区布局抗病品种能有效地推迟病害的发生时期，减慢病情的发展速度，且能减少农药施用量和施用次数，减少环境污染。

STUDY ON VARIETY RESISTANCE OF TOBACCO DEVELOPING PERIOD TO BROWN SPOT AND THE INTEGRATED MANAGEMENT TECHNIQUES

One to five lower leaves from tobacco pot plant of seven varieties were inoculated with brown spot pathogen Altemaria alternata. The result shows that the disease resistance decreased as the leaves become mature of senescent from bottom upward to top of tobacco plant when the leaf colour changed from green to yellow. Green growing leaf was immune while yellowish green leaf was highly resistant. The incidence of disease in mature leaf was highest. This indicates that the maturity of tobacco leaf was highly correlated with the resistance to brown spot disease. The result of field experiment showed that the resistance to tobacco brown spot was higher when the application of potash fertilizer was increased, topping was carried out later on a suitable date and the bottom 1-3 leaves were taken off just before mature period. Planting resistance cultivars when the disease was serious can put off or slow down the epidemic, reduce application of fungicides and environmental pollution.