Foot Disease Of Grapevine Research Articles

Biofumigation with <i>Brassica</i> spp for the control of cylindrocarpon black foot disease of grapevines

Green crops of Brassica species incorporated into the soil release volatile isothiocyanates which are known to suppress pathogenic fungal species Firstly crops of mustard (Brassica juncea) rape (B napus) and oats (Avena sativa) were grown for 5 weeks in a vineyard site previously infested with Cylindrocarpon spp The crops were cultivated into the soil and the area covered with polythene After 2 weeks callused cuttings of rootstock 101104 and 5C were grown for 9 months and infection assessed Disease incidence in rootstocks 10114 and 5C was reduced in the mustard treatment by 11 and 43 respectively The following year the site was inoculated with Cylindrocarpon spp grown on wheat grains The second experiment used three mustard treatments mustard meal cultivated into the soil (Trt 1) mustard grown once to flowering with cultivation (Trt 2) and mustard grown twice to flowering with cultivation each time (Trt 3) In rootstock 5C disease incidence was reduced in all treatments by more that 41 and in rootstock 10114 disease incidence was reduced in Trt 1 and 3 by 30 and 18 respectively These findings suggest that biofumigation using mustard may be a highly effective method for the control of Cylindrocarpon black foot disease

Analysis of genetic and virulence diversity of Cylindrocarpon liriodendri and C. macrodidymum associated with black foot disease of grapevine

Inter-simple sequence repeat (ISSR) analysis was used to investigate the genetic diversity of 87 Cylindrocarpon liriodendri and C. macrodidymum isolates, the causal agents of black foot disease of grapevine. The four ISSR primers (GT) 7, (CCA) 5, (CGA) 5 and (TCG) 5, were able to provide reproducible and polymorphic DNA fingerprint patterns and detected relevant genetic diversity in C. macrodidymum. The cluster analysis of ISSR data showed 21 different genotypes that were grouped in seven ISSR groups, from which two corresponded to C. liriodendri (G1 and G2) and five to C. macrodidymum (G3–G7). Nineteen isolates selected from the seven ISSR groups were inoculated in grapevine seedlings obtained from cv. ‘Tempranillo’. The pathogenicity tests detected virulence diversity in C. macrodidymum. The isolates belonging to ISSR groups G6 and G7 were significantly more virulent than the other C. macrodidymum and C. liriodendri isolates.

Characterization of Cylindrocarpon Species Associated with Black Foot Disease of Grapevine in Spain.

In this work, 82 Cylindrocarpon isolates associated with black foot disease of grapevines in Spain were studied by means of phenotypical characterization, DNA analyses, and pathogenicity tests. Partial sequences of the beta-tubulin (BT) gene, BT1, were amplified using primers BT1a and BT1b. A unique and conserved 52-bp insertion in the BT1 sequence, which is a specific marker for C. macrodidymum, was found in 56 of the isolates. The rest of the isolates (26) were identified as C. liriodendri. The BT phylogeny grouped all the isolates of each species into two well-supported clades. Phenotypical data were subjected to multivariate factorial analysis. According to this study, the isolates were clearly separated into two groups which were in agreement with BT species identification. C. macrodidymum isolates were differentiated from C. liriodendri by producing fewer conidia, presenting longer and wider macroconidia, and lower growth rate at 5 and 10°C. Selected isolates of each species inoculated onto rooted cuttings of grapevine rootstock cv. 110 R caused typical black foot disease symptoms. This is the first report of C. liriodendri and C. macrodidymum causing black foot disease of grapevines in Spain.

First Report of Cylindrocarpon liriodendri Causing Black Foot Disease of Grapevine in California.

Black foot disease is a recently identified but worsening problem in vineyards worldwide (2). Roots of symptomatic grapevines show black, sunken, necrotic lesions (2). In cross section, the base of the trunk appears necrotic and xylem vessels are plugged with black inclusions and tyloses (2). Aboveground, leaves of infected vines appear to be scorched, and the entire vine becomes stunted and frequently dies (2). In California, we previously identified two Cylindrocarpon species as causal agents of this disease: C. macrodidymum and C. destructans (2). In earlier molecular phylogenetic studies, tremendous variation in C. destructans from diverse hosts was found, indicating that this species might encompass more than one species (2). On the basis of analysis of sequences of three independent DNA regions, we concluded that the group of C. destructans isolated from grapevines in France, South Africa, and California have nearly identical sequences and form a well-supported sister clade divergent from the clade containing C. destructans found in numerous hosts (2). Further studies compared DNA sequences of C. destructans causing black foot in France, Portugal, and South Africa with an ex-type strain of C. liriodendri isolated from tulip poplar (Liriodendron tulipifera) (1). Because these species had identical sequences, C. destructans causing black foot in France, Portugal, and South Africa was renamed C. liriodendri (1). The objective of the current study was to clarify the taxonomy of C. destructans causing black foot in California. We compared C. liriodendri isolate CBS112602 from South Africa (1) with three C. destructans isolates (USME116, USST148, and USSO150) from California (2). We analyzed four sequences on three genomic regions: the internal transcribed spacer of ribosomal DNA, partial sequences of the beta tubulin gene, and the mitochondrial small subunit ribosomal DNA. We used sequences from the South African C. liriodendri isolate CBS112602 (AY997566, AY997586, AY997581, and AY997532) and sequences from Californian isolates of C. destructans (AY997568, AY997588, AY997534, AY997583, AY997569, AY997601, AY997547, AY997584, AY997570, AY997598, AY997544, and AY997585) previously deposited in GenBank (2). Sequences were aligned using Clustal X 1.8 (3). On the basis of visual inspection of each DNA region alignment, the South African C. liriodendri isolate was identical to Californian isolates of C. destructans. Thus, Californian isolates of C. destructans causing black foot (2) are renamed C. liriodendri. To our knowledge, this is the first report of C. liriodendri causing black foot disease of grapevine in California.

Control of black foot disease in grapevine nurseries

Black foot disease of grapevines is a decline and dieback disease caused by a soilborne pathogen complex including Cylindrocarpon liriodendri, C. macrodidymum, Campylocarpon fasciculare and Campyl. pseudofasciculare. These pathogens cause primary infections of roots and basal ends of grafted cuttings in nursery soils. Thirteen fungicides were screened in vitro for mycelial inhibition of these pathogens. Prochloraz manganese chloride, benomyl, flusilazole and imazalil were the most effective fungicides tested, and were subsequently included in semi‐commercial field trials. Basal ends of grafted cuttings were dipped in various chemical and biological treatments prior to planting in open‐rooted nurseries. Black foot pathogens were not isolated from grafted cuttings prior to planting. Additional treatments involved soil amendments with Trichoderma formulations and hot water treatment of dormant nursery grapevines. Field trials were evaluated after eight months. Isolations from uprooted plants revealed low levels of black foot pathogens in the roots of untreated control plants, and significantly higher levels in basal ends of rootstocks. The incidence of black foot pathogens, as well as that of Petri disease pathogens, was not significantly and/or consistently reduced by the majority of chemical or biological treatments. However, these pathogens were not isolated from uprooted plants that were subjected to hot water treatment. It is therefore recommended that hot water treatment of dormant nursery plants be included in an integrated strategy for the proactive management of these diseases in grapevine nurseries.

Neonectria liriodendri sp. nov., the main causal agent of black foot disease of grapevines

Black foot disease is a serious disease of grapevine crops in most areas where vines are grown. Mainly two species of Cylindrocarpon, C. destructans and C. macrodidymum, are associated with this disease. Recent studies have revealed a tremendous molecular variation within the former but only slight molecular variation within the latter, indicating that C. destructans presents a complex of several species The present study elucidates the taxonomic status of C. destructans-like isolates associated with black foot disease of grapevines. Grapevine isolates were studied morphologically, subjected to DNA analyses of their ITS and partial beta-tubulin genes, and were mated in all combinations in vitro. Cylindrocarpon destructans strains isolated from grapevines in Europe and South Africa appeared morphologically and genetically identical, and had identical ITS and partial beta-tubulin gene sequences. Phylogenetic analyses placed these strains in a clade closely related but clearly distinct from other clades with C. destructans-like anamorphs obtained from various herbaceous or woody hosts. Only the ex-type strain of Cylindrocarpon liriodendri had identical sequences to strains isolated from grapevines, and could also not be distinguished by morphological characters. The grapevine isolates are therefore reidentified here as Cylindrocarpon liriodendri. Cylindrocarpn liriodendri formed perithecia in heterothallic conditions and the holomorph of this species is described as Neonectria liriodendri sp. nov. Neonectria liriodendri is genetically distinct from the ex-type strain of Neonectria radicicola, which originated from Cyclamen in Sweden. Both ex-type strains also differ from at least two other clades comprising additional C. destructans-like strains. Many of these strains originated from Panax sp., which is the host of the type of C. destructans. Our phylogenetic analyses indicate that C. destructans is not the anamorph of N. radicicola and that N. liriodendri, N. radicicola and several C. destructans-like taxa may have evolved independently within the same phylogenetic species complex.

A Review of Black Foot Disease of Grapevine

Summary. Black foot disease of grapevine is a relatively new, and as yet poorly known disease affecting vines in various countries where grapevines are cultivated. The causal organisms, their distribution, associated symptoms, known epidemiology and possible management strategies are discussed. Specific attention is also given to the taxonomy of the fungi involved, and the detection methods being developed to facilitate rapid identification of these pathogens.

A Review of Black Foot Disease of Grapevine

A Review of Black Foot Disease of Grapevine

Characterization of Cylindrocarpon Species, the Cause of Black Foot Disease of Grapevine in California.

This study investigated phylogenetic divergence, morphological difference, and pathogenic variation among Cylindrocarpon species isolates associated with black foot disease of grapevine (Vitis sp.) in California. To assess phylogenetic divergence, we sequenced the internal transcribed spacer (ITS) of the nuclear ribosomal DNA (rDNA), partial beta-tubulin (BT) gene introns and exons, and the small subunit mitochondrial rDNA. Isolates associated with black foot disease belonged to two paraphyletic species, Cylindrocarpon destructans and C. macrodidymum. The morphology of these isolates was in agreement with published descriptions of both species. We found that C. macrodidymum isolates were reliably distinguishable from C. destructans isolates in culture by a unique orange-dark brown colony color on 2% malt extract agar and genetically by a species-specific 52-bp DNA insertion in the BT region. Selected isolates of each species inoculated onto grapevine rootstock 5C caused typical black foot disease symptoms. This is the first report of C. macrodidymum in California.