Piriformospora indica is a root endophytic fungus with plant-promoting properties in numerous plant species and induces resistance against root and shoot pathogens in barley, wheat, and Arabidopsis. A study over several years showed that the endophyte P. indica colonised the roots of the most consumed vegetable crop tomato. P. indica improved the growth of tomato resulting in increased biomass of leaves by up to 20%. Limitation of disease severity caused by Verticillium dahliae by more than 30% was observed on tomato plants colonised by the endophyte. Further experiments were carried out in hydroponic cultures which are commonly used for the indoor production of tomatoes in central Europe. After adaptation of inoculation techniques (inoculum density, plant stage), it was shown that P. indica influences the concentration of Pepino mosaic virus in tomato shoots. The outcome of the interaction seems to be affected by light intensity. Most importantly, the endophyte increases tomato fruit biomass in hydroponic culture concerning fresh weight (up to 100%) and dry matter content (up to 20%). Hence, P. indica represents a suitable growth promoting endophyte for tomato which can be applied in production systems of this important vegetable plant not only in soil, but also in hydroponic cultures.

王林发) 186 • Guoping Wang (王国平) 85 • Yanxiang Wang (王雁翔) 85 • Yaqin Wang (王亚琴) 38 • Muhammad Waqas 187 • Tàiyún Wèi (魏太云) 188 • Shaohua Wen (温少华) 85 • Anna E. Whitfield 189 • John V. Williams 190 • Yuri I. Wolf 99 • Jiangxiang Wu (吴建祥) 38 • Lei Xu (徐雷) 138 • Hironobu Yanagisawa (栁澤広 宣) 191 • Caixia Yang (杨彩霞) 69 • Zuokun Yang (杨作坤) 85 • F. Murilo Zerbini 192 • Lifeng Zhai (翟立峰) 193 • Yong-Zhen Zhang (张永振) 220,221 • Song Zhang (张松) 34 • Jinguo Zhang (张靖国) 194 • Zhe Zhang (张哲) 85 • Xueping Zhou (周雪平) 195

This chapter focuses on the epidemiology and management of forest diseases caused by viruses. Information is given on different pathogen detection methods (biological indexing, electron microscopic observations, antibody-based methods, doublestranded RNA-analysis, molecular hybridization and PCR), infection biology, transmission (through mechanical method, insect, nematode and fungal vectors, seeds, water and soil), as well as on the management strategies and tactics. Tabulated data are provided on economically important viruses detected in forest and roadside trees, as well as on main characteristics of Cherry leaf roll virus, European mountain ash ringspot-associated virus and of the graft-transmissible chlorotic ringspots of Quercus robur associated with a virus.

Since Emaraviruses have been discovered in 2007 several new species were detected in a range of host plants. Five genome segments of a novel Emaravirus from mosaic‐diseased Eurasian aspen (Populus tremula) have been completely determined. The monocistronic, segmented ssRNA genome of the virus shows a genome organisation typical for Emaraviruses encoding the viral RNA‐dependent RNA polymerase (RdRP, 268.2 kDa) on RNA1 (7.1 kb), a glycoprotein precursor (GPP, 73.5 kDa) on RNA2 (2.3 kb), the viral nucleocapsid protein (N, 35.6 kDa) on RNA3 (1.6 kb), and a putative movement protein (MP, 41.0 kDa) on RNA4 (1.6 kb). The fifth identified genome segment (RNA5, 1.3 kb) encodes a protein of unknown function (P28, 28.1 kDa). We discovered that it is distantly related to proteins encoded by Emaraviruses, such as P4 of European mountain ash ringspot‐associated virus. All proteins from this group contain a central hydrophobic region with a conserved secondary structure and a hydrophobic amino acid stretch, bordered by two highly conserved positions, thus clearly representing a new group of homologues of Emaraviruses. The virus identified in Eurasian aspen is closely associated with observed leaf symptoms, such as mottle, yellow blotching, variegation and chloroses along veins. All five viral RNAs were regularly detectable by RT‐PCR in mosaic‐diseased P. tremula in Norway, Finland and Sweden (Fennoscandia). Observed symptoms and testing of mosaic‐diseased Eurasian aspen by virus‐specific RT‐PCR targeting RNA3 and RNA4 confirmed a wide geographic distribution of the virus in Fennoscandia. We could demonstrate that the mosaic‐disease is graft‐transmissible and confirmed that the virus is the causal agent by detection in symptomatic, graft‐inoculated seedlings used as rootstocks as well as in the virus‐infected scions used for graft‐inoculation. Owing to these characteristics, the virus represents a novel species within the genus Emaravirus and was tentatively denominated aspen mosaic‐associated virus.

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The occurrence of Fusarium spp. and associated mycotoxins in asparagus spears was evaluated in Poland in 2002 and 2003 and in Germany in 2002. Spears of two cultivars, Eposs and Gijnlim, were collected from two locations in Poland, Swidwowiec and Poznan, on sandy and sandy loam soil, respectively. Fusarium oxysporum and F. proliferatum were detected at an average incidence of 38.3% and 15.8% in the spear sections sampled, respectively. In stands of 11 (tested) cultivars of asparagus sampled in Germany on sandy soil, the same species dominated, however, they were less frequent than in Poland (26.6% and 5.6% of the spears infected with F. oxysporum and F. proliferatum, respectively). Chemical analyses revealed that fumonisin B 1 (FB 1 ) and moniliformin (MON) were present in some of the spears sampled in Poland. FB 1 was not found and MON was not assessed in spears sampled in Germany in 2002, but F. proliferatum was able to form the toxin in vitro in the range from 101.4 up to 205.8 lg/kg maize kernel substrate. Asparagus samples in Poland contained FB 1 at up to 5.6 lg/kg spear fresh weight. The highest MON concentration (1350 lg/kg) was detected in cultivar Eposs in Marcelin, Poland, in 2002. MON and FB 1 were found in spears infected by both F. oxysporum and F. proliferatum, however, only the latter fungus was able to synthesize both toxins.www.blackwell-synergy.com

Fusarium proliferatum (teleomorph: Gibberella intermedia) is a causal agent of crown rot of Asparagus officinalis and is one potential fumonisin-producing species within the genus Fusarium. It colonizes roots and crowns of asparagus plants, but could also be isolated from symptomless asparagus spears. Fusarium proliferatum isolates obtained from perennial asparagus plantings from Austria and Germany were included in a study on detectability and variability of two essential genes of the fumonisin-gene cluster. Genetic fingerprinting of 45 isolates revealed 14 different fingerprint groups, indicating genetic heterogenicity of F. proliferatum. Most isolates differentiated into three main fingerprint clusters, but no association was found between fingerprint group and origin of the isolates. By gene-specific PCR it was shown that, in 25 isolates tested, both initial genes of the fumonisin biosynthetic pathway -FUM1, encoding a polyketide synthase and FUM8, a gene for a putative aminoacyl transferase -were detectable. This suggests that these isolates were able to produce fumonisins and could contribute to the detected contamination in originating asparagus spears with this mycotoxin. Thus, early detection of FUM-genes in F. proliferatum-colonized asparagus may be suited to prevent uptake of fumonisin contaminated food with the human diet. Restriction fragment length polymorphism analysis (PCR-RFLP) of the amplified FUM gene fragments revealed little sequence variability, suggesting a conserved structure of these genes within this species. However, sequence analysis confirmed intraspecific nucleotide polymorphisms of these genes.