Abstract

Powdery mildews are some of the most common and dangerous biotrophic plant pathogens. They attack more than 10, 000 plant species, and can be found mainly in temperate and sub-tropical zones. This review evaluates the effects of most important abiotic conditions on powdery mildew namely temperature, humidity, light quality, air composition (mainly CO₂ and ozone concentration) and movement. With the most intensively studied factors, temperature and humidity, powdery mildew species vary in their requirements, this variation occurring in different phases of their life cycle. Generally, temperatures between 13 and 30 °C were optimal for their development, with conidial germination being the least and sporulation the most affected part of the life cycle and lower marginal temperatures only prolonging the latent period. The role of moisture in their development is more elusive; free moisture inhibits dispersal and germination of conidia and extension of hyphae of most powdery mildews. However, for further development high relative humidity is preferred and free water is required for release and dispersal of ascospores. Light most affects the pathogen indirectly through its effect on the host. Although germination and appressorial maturation is possible under low illumination and darkness, light is needed for completion of the disease cycle. A suitable photoperiod (alternating day and night) favors optimal development, e.g., continuous light reduces infection. The effect of CO₂ concentration is complex; sometimes an increased concentration of CO₂ causes more intensive disease, sometimes less or no effect at all. Most environmental factors also affect the host thus affecting the pathogen indirectly; other factors (e.g. UV or CO₂) mainly directly affect the pathogen. Hypotheses on the possible effect of predicted climate change on pathosystems are discussed.

摘要

白粉病是一些最常见和最危险的生物营养型植物病原体。它们攻击 10, 000 多种植物，主要​​分布在温带和亚热带地区。本综述评估了最重要的非生物条件对白粉病的影响，即温度、湿度、光照质量、空气成分（主要是 CO ₂和臭氧浓度）和运动。由于研究最深入的因素，温度和湿度，白粉病物种的要求各不相同，这种变化发生在它们生命周期的不同阶段。一般来说，13 到 30 °C 之间的温度最适合它们的发育，分生孢子萌发最少，孢子形成是生命周期中受影响最大的部分，较低的边缘温度只会延长潜伏期。水分在它们发育中的作用更难以捉摸；游离水分抑制分生孢子的散布和萌发以及大多数白粉病菌丝的延伸。然而，为了进一步发展，高相对湿度是优选的，并且子囊孢子的释放和分散需要游离水。光通过其对宿主的影响间接地影响病原体。尽管在低光照和黑暗条件下发芽和附着成熟是可能的，但完成疾病周期需要光照。合适的光周期（白天和黑夜交替）有利于最佳发育，例如，连续光照可减少感染。一氧化碳的影响₂浓度复杂；_{有时，CO 2}浓度的增加会导致更严重的疾病，有时影响较小或根本没有影响。大多数环境因素也会影响宿主，从而间接影响病原体；其他因素（如紫外线或CO ₂）主要直接影响病原体。讨论了预测的气候变化对病理系统可能产生的影响的假设。