Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Las enfermedades de la madera se encuentran entre las patologías más dañinas que afectan al cultivo de la vid. El pie negro es una de las más destacadas, afectando a las plantas en vivero y en plantaciones jóvenes. Los agentes causales están incluidos dentro de los géneros Campylocarpon, ¿Cylindrocarpon¿, Cylindrocladiella e Ilyonectria. Éstos se caracterizan por ser habitantes del suelo y, se ha demostrado que permanecen en él, infectando al material de propagación cultivado en campos de vivero. La presencia de hongos asociados al pie negro en vivero, así como sus fuentes potenciales de inóculo en suelos de vivero y de viñedos comerciales, no han sido nunca estudiados en España. En este sentido, el objetivo de esta Tesis ha sido estudiar la epidemiología de hongos que causan el pie negro de la vid en España. En primer lugar, las distintas fases del proceso viverístico se evaluaron como fuentes potenciales de inóculo de estos patógenos. Se tomaron muestras en cuatro fases del proceso de propagación de las que se extrajo el ADN, detectándose las especies causantes del pie negro de la vid mediante multiplex, nested PCR. En las fases estudiadas se detectaron I. liriodendri y el complejo I. macrodidyma. También se estudió la detección de especies de Ilyonectria en material de propagación de vid, antes y después de la fase de enraizamiento en campos de vivero, mediante técnicas de aislamiento y multiplex, nested PCR. Este estudio confirmó que el número de plantas infectadas con estos patógenos aumenta durante el proceso de enraizamiento en campos de vivero. Ilyonectria torresensis fue la única especie aislada de las plantas tras la inducción del callo. Sin embargo, las especies I. liriodendri, I. novozelandica e I. torresensis se aislaron frecuentemente tras el período de cultivo en campos de vivero. Respecto a la detección molecular, se detectaron un número elevado de muestras positivas en planta tras la inducción del callo y después del proceso de enraizamiento. Mediante el uso de cuatro técnicas diferentes, aislamiento fúngico a partir de raíces de plántulas de vid utilizadas como plantas trampa, aislamiento a partir de raíces de malas hierbas, multiplex, nested PCR y qPCR, se estudió el suelo de campos de plantas madre como fuente de inóculo de estos patógenos. De las raíces de plantas trampa se aislaron las especies I. alcacerensis, I. macrodidyma, I. novozelandica e I. torresensis. ¿Cylindrocarpon¿ macrodidymum fue la única especie aislada de las raíces de malas hierbas. En los análisis de suelos realizados mediante multiplex, nested PCR así como mediante qPCR se observó un elevado porcentaje de detección del complejo I. macrodidyma en muestras de ADN de suelo, mientras que el porcentaje de detección de I. liriodendri fue menor. Las mismas técnicas descritas para campos de plantas madre se utilizaron para estudiar los suelos de campos de vivero y de viñedos comerciales. Los resultados obtenidos en estos dos tipos de campos fueron similares a los obtenidos en campos de plantas madre. Finalmente, se estudió el efecto de la temperatura, pH y potencial osmótico (¿s) sobre el crecimiento miceliar, la esporulación y la producción de clamidosporas de ¿C.¿ liriodendri, ¿C.¿ macrodidymum y ¿C.¿ pauciseptatum, con el objetivo de mejorar el conocimiento de los factores que afectan al crecimiento, reproducción y supervivencia de estos patógenos. Todos los aislados estudiados crecieron en un rango de temperaturas comprendido entre 5 y 30ºC. Se observó crecimiento miceliar en un rango de pH comprendido entre 4 y 8. Respecto al efecto del ¿s, el crecimiento miceliar fue mejor en medio de cultivo PDA ajustado a -0,5, -1,0 y/o -2,0 MPa en comparación con el crecimiento miceliar observado en PDA sin ajustar a ningún ¿s (-0,3 MPA). La mayoría de los aislados de ¿Cylindrocarpon¿ esporularon a todas las temperaturas, pHs y valores de ¿s estudiados. En general, la producción de clamidosporas no se vio afectada por la temperatura, el pH y el ¿s. / Agustí Brisach, C. (2013). Studies on the epidemiology of black-foot disease of grapevine in Spain [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/27598 / TESIS

Dissertation (PhD (Agric))--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: During the past few years a drastic reduction has been noted in the survival rate of grafted grapevines in nurseries, as well as in young vineyards in the Western Cape Province of South Africa. Circumstantial evidence suggested that Cylindrocarpon spp., which cause black foot disease of grapevine, were associated with this decline. Black foot disease of grapevine is a relatively new, and as yet poorly known disease affecting vines in various countries where grapevines are cultivated. Primary aims of this research have been (1) to conduct nursery surveys in order to determine which fungi are involved in the decline phenomenon, with special reference to the involvement of Cylindrocarpon spp., (2) to identify and characterise the organisms believed to be the causal organisms of black foot disease, and (3) the development of control and/or management strategies to prevent or eradicate Cylindrocarpon infections. Nursery grapevines were sampled at different stages from three commercial nurseries in the Wellington area of the Western Cape Province and were investigated during the 19992000 season by means of destructive sampling. The first samples were taken in September from callused cuttings prior to planting in nurseries. After planting, asymptomatic rooted cuttings were selected from nurseries after 3, 6 and 9 months. Isolation studies clearly demonstrated that different “Cylindrocarpon spp.” infected cuttings from nursery soils. These species rarely occurred in rootstock propagation material prior to planting. At the time of planting, the susceptible basal ends (especially the pith area) of most of the nursery cuttings are partly or even fully exposed. Callus roots also break during the planting process, resulting in small wounds susceptible to infection by soilborne pathogens. The isolation studies revealed that the first infections occurred in the roots, followed by infections of the rootstocks. These infections increased progressively during the course of the growing season. Substantial variation in cultural and morphological characters was observed among the Cylindrocarpon isolates obtained from the nursery survey, as well as from isolations that were made from diseased grapevines. Morphological and phylogenetic studies were conducted to identify these “Cylindrocarpon spp.” and to establish their association with black foot disease. Sequences of the partial nuclear large subunit ribosomal DNA (LSU rDNA), internal transcribed spacers 1 and 2 of the rDNA including the 5.8S rDNA gene (ITS), and partial β-tubulin gene introns and exons were used for phylogenetic inference. Phylogenetic analyses confirmed the diversity observed among the isolates and four Cylindrocarpon-like species were identified. One of these species was initially identified as Cylindrocarpon destructans. However, further research revealed C. destructans to represent a species complex. Grapevine isolates of “C. destructans” proved to be identical to the ex-type strain of Cylindrocarpon liriodendri, which also produced a teleomorph, Neonectria liriodendri in culture. A second species was newly described in this study as Cylindrocarpon macrodidymum (Neonectria macrodidyma). The two remaining Cylindrocarpon-like species were placed in a new genus, Campylocarpon. The two species were named Campylocarpon fasciculare and Campylocarpon pseudofasciculare. Pathogenicity studies confirmed that all four species were able to reduce root and shoot mass significantly. Knowledge obtained pertaining to the disease cycle of black foot disease suggest that suitable management strategies should focus on prevention of primary infection in nurseries. However, at present, no fungicides are registered for control of this disease in South African vineyards or nurseries. 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 (1 min) 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 in nurseries. Additional treatments involved soil amendments with Trichoderma formulations and hot water treatment (50°C for 30 min) of dormant nursery grapevines. Field trials were evaluated after a growing season of eight months. The incidence of black foot 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 black foot disease in grapevine nurseries. / AFRIKAANSE OPSOMMING: Gedurende die afgelope paar jaar is ‘n drastiese afname waargeneem in die sukses van geënte wingerdplante in kwekerye, sowel as jong wingerde van die Wes-Kaap. Omstandigheidsgetuienis dui daarop dat Cylindrocarpon spp., wat die wingerdsiekte swartvoet veroorsaak, geassosieer word met hierdie agteruitgang. Swartvoet is ‘n relatiewe nuwe siekte waarvan daar baie min inligting bekend is, alhoewel dit voorkom in verskeie lande waar wingerd verbou word. Die primêre doel van navorsing was (1) om opnames in wingerdkwekerye uit voer om te bepaal watter swamme betrokke is by die verskynsel van agteruitgang, met spesiale verwysing na die betrokkenheid van Cylindrocarpon spp., (2) om die organismes te identifiseer en te karakteriseer wat daarvan verdink word dat hulle die siekte swartvoet veroorsaak, en (3) om beheer en/of bestuurspraktyke te ontwikkel om Cylindrocarpon infeksies te voorkom of uit te wis. Kwekeryplantjies in drie kommersiële kwekerye in die Wellington omgewing van die Wes-Kaap is gedurende verskillende tye gedurende die groeiseisoen gemonitor. Die opnames het plaasgevind gedurende die 19992000 seisoen deur middel van destruktiewe monsterneming. Die eerste monsters is geneem in September nadat die stokkies geënt en gekallus is en voordat dit in die kwekery geplant is. Na plant is asimptomatiese, gewortelde plante vanuit die kwekerye na 3, 6 en 9 maande uitgehaal. Isolasiestudies dui duidelik daarop dat verskillende “Cylindrocarpon spp.” plante vanuit die kwekerygrond geïnfekteer het. Hierdie spesies het selde voorgekom in onderstok-voortplantingsmateriaal voor plant. Tydens plant is die vatbare basale gedeelte, veral die pit, van die meeste geënte stokkies gedeeltelik of selfs volledig blootgestel. Kalluswortels breek ook tydens plant wat wonde laat vir infeksie deur grondgedraagde siektes. Die isolasiestudies dui ook daarop dat die eerste infeksies in die wortels plaasgevind het, gevolg deur infeksies van die onderstokke. Hierdie infeksies het toenemend voorgekom gedurende die verloop van die groeiseisoen. Substansiële variasie in kultuur- en morfologiese eienskappe is waargeneem in die Cylindrocarpon isolate wat tydens die kwekeryopnames versamel is, sowel as van isolasies wat gemaak is uit siek plante. Morfologiese en filogenetiese studies is uitgevoer om hierdie “Cylindrocarpon spp.” te identifiseer en hul betrokkenheid by die siekte swartvoet uit te klaar. Gedeeltelike DNS volgordes van die groot ribosomale subeenheid (“LSU rDNA”), interne getranskribeerde spasiëerderarea (“ITS1, “ITS2”), insluitend die 5.8S rRNS geen, en gedeeltelike β-tubilien geen introns and eksons is gebruik vir filogenetiese analise. Filogenetiese analises het die diversiteit wat waargeneem is tussen die verskillende isolate bevestig deurdat vier Cylindrocarpon-agtige spesies geïdentifiseer is. Een van hierdie spesies is aanvanklik geïdentifiseer as Cylindrocarpon destructans. Verdere navorsing het egter daarop gedui dat C. destructans ‘n spesie-kompleks verteenwoordig. “C. destructans” afkomstig van wingerd blyk identies te wees aan die ex-tipe isolaat van Cylindrocarpon liriodendri, wat ook ’n teleomorf, Neonectria liriodendri in kultuur vorm. ’n Tweede spesie is nuut beskryf in hierdie studie as Cylindrocarpon macrodidymum (Neonectria macrodidyma). Die twee oorblywende Cylindrocarpon-agtige spesies is geplaas in ‘n nuwe genus, Campylocarpon. Die twee spesies staan bekend as Campylocarpon fasciculare en Campylocarpon pseudofasciculare. Patogenisiteitstudies het bevestig dat al vier spesies die vermoë het om wortel- en lootmassa van wingerdplant drasties te verlaag. Kennis wat opgedoen is rakende die lewensiklus van swartvoet dui daarop dat bestuurspraktyke daarop moet fokus om primêre infeksies in wingerdkwekerye te voorkom. Op die oomblik is daar egter geen fungisiedes geregistreer vir die beheer van die siekte in Suid- Afrikaanse wingerde of kwekerye nie. Dertien fungisiedes is in vitro geëvalueer om te bepaal of dit miseliumgroei van hierdie swamme kan inhibeer. Prochloraz mangaan chloried, benomyl, flusilasool en imazalil was die effektiefste fungisiedes wat ondersoek is, en is gevolglik ingesluit in semi-kommersiële veldproewe. Die basale gedeelte van geënte stokkies is gedoop (1 min) in verskeie chemies en biologiese behandelings voordat dit geplant is in die kwekerye. Patogene wat geassosieer word met swartvoet is nie vanuit geënte stokkies geïsoleer voordat dit in die kwekerye geplant is nie. Addisionele behandelings het bestaan uit grondtoevoegings met Trichoderma formulasies, sowel as warmwaterbehandeling (50°C vir 30 min) van dormante kwekeryplante. Die veldproewe is geëvalueer na ‘n groeiseisoen van 8 maande. Die voorkoms van swartvoet patogene is nie betekenisvol/konstant verlaag deur die meeste chemies en biologiese behandelings nie. Hierdie patogene is egter nie vanuit plante geïsoleer wat na uithaal aan warmwaterbehandeling blootgestel is nie. Dit word dus aanbeveel dat warmwaterbehandeling van dormante kwekeryplante deel word van ‘n geïntegreerde strategie vir die pro-aktiewe beheer van swartvoet in wingerdkwekerye.

Thesis (M. Sc.) -- Lincoln University, 2009. / Also available via the World Wide Web.

The overall goal of this research was to determine what, if any, role grapevine rhizosphere bacteria play in the differing susceptibilities of New Zealand grown rootstocks to Cylindrocarpon black foot disease. The size and diversity of bacterial populations associated with the rhizospheres of grapevine rootstocks: 101-14, 5C, Schwarzmann and Riparia Gloire were evaluated. Dilution plating showed that total bacterial (P=0.012, P=0.005 for NA and KB, respectively) and fluorescent Pseudomonad (P=0.035) rhizosphere counts differed between rhizosphere and bulk soils but did not correlate with the differing susceptibilities of the rootstock varieties to black foot. No varietal differences were found for spore forming bacteria (P=0.201). SSCP banding patterns showed that species diversity was similar for most rootstocks, but that there were some differences in the composition of bacterial populations, probably attributable to vigour. Some functional characteristics of the bacteria isolated from the rhizospheres of the most and least susceptible rootstock varieties were assessed to investigate their potential to suppress the pathogen. In dual culture, bacteria from Riparia Gloire, 101-14 and the control soil all had little ability to antagonise Cylindrocarpon destructans. However, they differed in their degrees of activity for glucanase (P=0.000), protease (P=0.001) and siderophores (P=0.000). In all tests, bacterial isolates from the rhizosphere of 101-14 had the largest number of active isolates (P≤0.002); however, those from Riparia Gloire had the greatest degree of positive responses for the glucanase and siderophore assays. Bacterial isolates from the control soil produced few glucanases and no siderophores, but had the highest degree of protease activity. Bands excised and sequenced from SSCP gels frequently matched to other ‘uncultured bacteria’ in GenBank, as well as to other bacterial phyla, classes and genera commonly isolated from soil and sediment samples. These included members of the Firmicutes, Proteobacteria (α, δ, γ), Verrucomicrobia, Acidobacteria and Chromatiales. The pathogenicity of C. destructans and Fusarium oxysporum was investigated by inoculating soil containing wounded ungrafted rootstocks of 101-14, 5C, Schwarzmann and Riparia Gloire. Results indicated that F. oxysporum might be a more aggressive pathogen than C. destructans. Inoculation with F. oxysporum or C. destructans increased disease severity, P=0.018 and P=0.056, respectively at 0 cm. Rootstock variety influenced disease severity caused by C. destructans (P<0.001) and F. oxysporum (P=0.090), with rootstocks 101-14 and 5C being most susceptible to C. destructans, and Riparia Gloire and Schwarzmann most susceptible to F. oxysporum. There was also an indication that inoculation with one pathogen increased plant susceptibility to the other, with increased F. oxysporum infection in the C. destructans inoculated treatments of Riparia Gloire and Schwarzmann (P<0.05). The effect of carbohydrate stress (leaf trimming) and inoculation on C. destructans disease severity, incidence, and rootstock rhizosphere bacterial populations was evaluated by inoculating the soil containing one year old plants of Sauvignon Blanc scion wood grafted to rootstocks 101-14 and Schwarzmann. Disease severity and incidence was similar for both Schwarzmann (8.4% and 29.3%, respectively) and 101-14 (14.9% and 31.0%, respectively). When data for the moderate and no stress treatments were combined, because their effects were similar, the disease severity was significantly higher for the highly stressed plants(P=0.043). Stress did not influence disease incidence (P=0.551). Infection occurred in the non-inoculated plants, but disease severity was higher in the plants inoculated with C. destructans than those that were not. Root dry weight of highly stressed plants was lower than in both the moderately stressed (P=0.000) and unstressed plants (P=0.003). An interaction between inoculation and stress (P=0.031) showed that inoculated and highly stressed plants had the lowest root dry weight but there was no effect of rootstocks (P=0.062). There was no significant effect of carbohydrate stress (P=0.259) or inoculation (P=0.885) on shoot dry weight. SSCP banding patterns showed that bacterial diversity was generally similar between rootstocks, but stress and inoculation altered rhizosphere bacterial communities. This study has demonstrated that functionality of grapevine rhizosphere bacteria do differ between grapevine rootstock varieties that have different susceptibilities to black foot disease, but that this role needs to be further investigated if more accurate and practically relevant conclusions are to be drawn.