Maccarone L D
School of Earth & Environment, The University of Western Australia.
Plant Dis. 2013 Jun;97(6):700-707. doi: 10.1094/PDIS-10-12-0979-FE.
Lettuce big-vein disease (LBVD) is a widespread problem in commercial lettuce producing areas. It was first reported in 1934 in California. In the United States in 2009, it was estimated that 100% of all commercial lettuce production was concentrated in California (in early spring) and Arizona (in winter). The disease also occurs worldwide, particularly in regions in Australia, Europe, Brazil, and New Zealand, and at high altitudes in subtropical regions. LBVD often results in decreased yield from infected plants, mainly in winter growing seasons. Symptoms of this disease are the obvious chlorophyll clearing, which causes the big-vein leaf symptoms from which the disease gets its name, along with crinkled leaves and a reduced head size, which is often oblong in shape. LBVD is associated with a complex of two viruses, Lettuce big-vein associated virus (LBVaV) and Mirafiori lettuce big-vein virus (MLBVV). Motile zoospores of Olpidium virulentus vector LBVaV and MLBVV to the roots of healthy plants and, in the absence of susceptible hosts, its resting spores retain the ability to harbor these viruses for decades in infested soil and in dry roots for 39 months. The ability of viruliferous resting spores to persist in production areas for such extended periods of time, and also the motility of viruliferous zoospores, pose significant difficulties for the management and/or control of the disease.
生菜大脉病（LBVD）是商业生菜产区普遍存在的问题。该病于1934年在加利福尼亚首次报道。2009年在美国，据估计所有商业生菜生产的100%集中在加利福尼亚（早春）和亚利桑那州（冬季）。该病在全球也有发生，特别是在澳大利亚、欧洲、巴西和新西兰的一些地区，以及亚热带地区的高海拔地带。LBVD通常会导致受感染植株产量下降，主要发生在冬季生长季节。这种病的症状是叶绿素明显消退，导致叶片出现大脉症状，该病也因此得名，同时叶片皱缩，叶球变小，叶球形状通常为长椭圆形。LBVD与两种病毒的复合体有关，即生菜大脉相关病毒（LBVaV）和米拉菲奥里生菜大脉病毒（MLBVV）。致病腐霉的游动孢子将LBVaV和MLBVV传播到健康植株的根部，在没有易感寄主的情况下，其休眠孢子能够在受侵染的土壤中以及干燥的根部携带这些病毒数十年（在干燥根部可携带39个月）。带毒休眠孢子在产区如此长时间的存活能力，以及带毒游动孢子的游动性，给该病的管理和/或防治带来了巨大困难。
