Viruega J R, Moral J, Roca L F, Navarro N, Trapero A
Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071-Córdoba, Spain.
Plant Dis. 2013 Dec;97(12):1549-1556. doi: 10.1094/PDIS-12-12-1206-RE.
Olive scab caused by the mitosporic fungus Spilocaea oleagina is the most important foliar disease of olive. Limited information is available on pathogen survival and disease epidemiology; however, this information is essential for development of new control strategies. Pathogen survival and inoculum production on infected olive leaves and conidial dispersal were evaluated during 4 years in an olive orchard of the susceptible 'Picual' in southern Spain. Infected leaves in the tree canopy were important for pathogen survival and conidia production. The number of conidia per square centimeter of scab lesion and their viability varied greatly throughout the seasons and between years; conidial density in lesions was highest (about 1 to 5 × 10 conidia cm) from November to February in favorable years. Conidial density declined sharply in other periods of the year (becoming zero in summer) or in less favorable years. The pathogen did not form new conidia in scab lesions, although some pseudothecia-like structures and chlamydospores were detected on fallen leaves. Under humid conditions, the pathogen could not be detected on fallen leaves after 3 months because the leaves were colonized by saprophytic fungi. The dispersal of conidia as a function of distance from infected leaves in the tree canopy was well described by an exponential model which, together with the lack of conidia in a Burkard spore trap, showed that conidia were mainly rain-splash dispersed. Some trapped conidia were attached to olive leaf trichomes, suggesting that detached trichomes might enhance wind dispersal of conidia.
由半知菌亚门真菌油橄榄盘二孢菌引起的油橄榄疮痂病是油橄榄最重要的叶部病害。关于病原菌存活和病害流行病学的信息有限；然而，这些信息对于制定新的防治策略至关重要。在西班牙南部易感品种‘皮夸尔’的一个油橄榄果园中，对病原菌在受感染油橄榄叶片上的存活、接种体产生以及分生孢子传播进行了为期4年的评估。树冠层中受感染的叶片对病原菌存活和分生孢子产生很重要。每平方厘米疮痂病斑上的分生孢子数量及其活力在不同季节和年份间差异很大；在适宜年份，11月至2月病斑中的分生孢子密度最高（约1至5×10个分生孢子/平方厘米）。在一年中的其他时期（夏季变为零）或不太适宜的年份，分生孢子密度急剧下降。病原菌在疮痂病斑中不形成新的分生孢子，尽管在落叶上检测到了一些假囊壳状结构和厚垣孢子。在潮湿条件下，3个月后在落叶上检测不到病原菌，因为叶片被腐生真菌定殖。用指数模型很好地描述了树冠层中分生孢子从受感染叶片传播的距离函数，该模型与Burkard孢子捕捉器中没有分生孢子一起表明，分生孢子主要通过雨滴飞溅传播。一些捕获的分生孢子附着在油橄榄叶毛状体上，这表明脱落的毛状体可能会增强分生孢子的风力传播。
