The growth-stimulating attributes of Trichoderma treatments (dips, soil amendments and drenches with Trichoderma products containing propagules of selected strains of Trichoderma harzianum) in ...grapevine nurseries, and their effect on the occurrence of fungi in roots and rootstocks of nursery grapevines, in particular fungi causing Petri disease (Phaeomoniella chlamydospora and Phaeoacremonium spp.) and black foot rot (Cylindrocarpon spp.), were compared with quintozene/procymidone treated (standard) vines. Early shoot growth of Trichoderma treated vines was visibly better than that of the control vines. Eight months after planting, at uprooting, percentage take and shoot mass of Trichoderma and standard treated vines were similar, but total root mass was significantly higher for Trichoderma treated vines. Low percentages of Cylindrocarpon spp. were isolated from the rootstocks of treated and untreated vines, while less Petri disease fungi were isolated from rootstocks oí Trichoderma treated vines. Markedly fewer fungi were also isolated from the roots oí Trichoderma treated vines. Incidences of Petri disease fungi in roots oiTrichoderma and standard treated vines were similar, but fewer Cylindrocarpon spp. were isolated from Trichoderma treated vines. These results indicate the potential oiTrichoderma treatments in grapevine nurseries for the production of stronger vines with lower PhaeomoniellalPhaeoacremonium and Cylindrocarpon infection levels.
Twenty healthy cuttings each were inoculated artificially with Phaeomoniella chlamydospora Phaeoacremonium inflatipes and Phaeoacremonium aleophilum. After the formation of callus, they were planted ...in pots. Approximately one year after inoculation, disease occurrence was recorded as the length of brown vascular streaking from the base of plant toward the shoot tip. Discolored areas were cultured on potato dextrose agar amended with tetracycline hydrochloride (PDA-tet) and pathogens were re-isolated. Inoculation with Pa. chlamydospora showed that rootstocks 3309, 420A, 110R, 5C, Schwarzmann, St. George, and Salt Creek were least susceptible, while 99R, 39-16, Freedom, Riparia Gloire, 140Ru, 16-16 and 1103 were most susceptible. When inoculated with Pm. inflatipes, 16-16,3309, AXR1, Salt Creek, 110R, 5C, Freedom and 140Ru were least susceptible, while 420A, St. George, 161-49, and Harmony were most susceptible. Inoculation with Pm. aleophilum showed that 1103, 420A, Harmony, and Salt Creek were least susceptible, while 110R, SO4, 39-16 and 161-49 were most susceptible. The susceptibility of the rootstocks and the occurrence of vine decline in the field in California did not appear to be well correlated because 3309, 101-14, 5C, and 110R were always most susceptible. But these rootstocks are the most widely planted, and hence the natural occurrence of the disease is probably skewed towards these rootstocks. However, since no resistance was detected in our study, even though there was a wide range of susceptibility, the degree of rootstock susceptibility may not be such an important factor in disease expression under natural conditions.
Many grapevine nurseries are presently employing a hot-water treatment for propagation material as a prophylactic measure. The aim of this study was thus to determine the efficacy of this treatment ...in eliminating fungal endophytes from grapevine cuttings. The number of fungal colonies isolated from the hot-water treated cuttings six months after planting were not, however, significantly different (P = 0.05) from that of the untreated cuttings. This was in contrast to when isolations were made directly after treatment, when no known living fungal pathogens were found inside treated vine tissue. These results therefore indicate that the hot-water treatment is effective in eliminating the most well-known fungal pathogens and endophytes from grapevine tissue. Further research now needs to be focused on combining this treatment with biological control agents, in an attempt to delay recolonisation of tissue by fungal pathogens
Molti vivai viticoli stanno utilizzando attualmente un trattamento con acqua calda come misura profilattica per il materiale di propagazione. Lo scopo di questo studio consisteva quindi nel determinare l'efficacia di questo trattamento ai fini dell'eliminazione dei funghi endofiti dalle talee di vite. Il numero delle colonie fungine isolate dalle talee trattate con acqua calda sei mesi dopo la messa a dimora non e' risultato, comunque significativamente differente (P = 0,05) da quello relativo alle talee non trattate. Questo dato era in contrasto con quello ottenuto effettuando l'isolamento subito dopo il trattamento, caso in cui non si ritrovavano patogeni fungini vitali nei tessuti delle piante trattate. Questi risultati indicano percio' che il trattamento con acqua calda e' efficace per l'eliminazione dei patogeni fungini piu' conosciuti dai tessuti delle viti. Attualmente e' necessario indirizzare ulteriori ricerche alla combinazione di questo trattamento con agenti di controllo biologico nel tentativo di ritardare la ricolonizzazione del tessuto da parte dei patogeni fungini
Hot water treatments were applied to eradicate Phaeoacremonium inflatipes and Phaeomoniella chlamydospora from dormant grapevine wood. A thirty-minute hot water treatment at 51 deg C did not ...eliminate these pathogens from dormant wood cuttings. Cuttings first inoculated with Pa. chlamydospora or Pm. inflatipes or both fungi and then subjected to a hot water treatment were either incubated on crispers or planted for six to eight weeks. Vascular discoloration was scored, followed by isolation from the cuttings onto potato dextrose agar amended with 0.1 g l*-1) tetracycline (PDA-tet). Isolations confirmed the presence of the pathogens in the inoculated, hot-water treated cuttings as well as in the inoculated, untreated control cuttings. This finding, along with earlier research on the direct effect of hot water on the mycelium of these species, leads to the conclusion that hot water treatments are ineffective in eliminating vine decline pathogens from dormant wood
Sono stati effettuati trattamenti con acqua calda per eliminare Phaeoacremonium inflatipes e Phaeomoniella chlamydospora dal legno quiescente di vite. Un trattamento di trenta minuti con acqua calda a 51 gradi C non sopprimeva questi patogeni nelle talee legnose in riposo. Le talee, prima inoculate con Pa. chlamydopsora o Pm. inflatipes o ambedue i funghi e successivamente soggette a un trattamento con acqua calda, sono state incubate in cestelli o piantate per un periodo da sei a otto settimane. E' stata valutata la scoloritura vascolare, cui e' seguito l'isolamento dalle talee su agar destrosio patata addizionato con 0,1 g l*-1) di tetraciclina (PDA-tet). Gli isolamenti hanno confermato la presenza dei patogeni sia nelle talee trattate con acqua calda, inoculate, sia nei controlli inoculati. Questi risultati, unitamente a quelli derivanti da precedenti ricerche sull'effetto diretto dell'acqua calda sul micelio di queste specie, fanno concludere che i trattamenti con acqua calda non sono in grado di eliminare i patogeni del deperimento della vite dal legno quiescente
Current seed health testing is based on standardised methods described by International Seed Testing Association (ISTA) working sheets. Some of these tests are slow, insensitive and labour intensive. ...Molecular diagnostics offers the potential for sensitive and specific detection of pathogens and for detection of more than one pathogen in a single test by multiplex PCR and/or the use of fluorescent probes or primers. These methods are also suitable for automation and are thus more time and cost-effective than conventional methods. There are a multitude of primer sets designed from sequence characterised amplified regions (SCAR) and internal transcribed spacer (ITS) sequence data that have been published and developed for identifying plant pathogens. However, only a limited number of these have been developed into seed health tests. This may be partly due to technical difficulties, cost of PCR license and royalties, as well as the time and organisation needed for test standardisation. In the near future it is anticipated that improved tests developed from current PCR/probe systems, and from future DNA chip technology, will help to reduce the amount of prophylactic seed treatment and improve management of seed-borne diseases
L'attuale sistema di verifica della sanita' delle sementi e' basato su test standardizzati descritti dalle schede di lavoro dell'International Seed Testing Association (ISTA). Alcuni di questi test sono lenti, poco sensibili e laboriosi. La diagnostica molecolare offre il potenziale per un'individuazione sensibile e specifica dei patogeni e per determinare la presenza di piu' di un patogeno in un singolo test mediante la PCR multiplex e/o l'impiego di sonde o primer fluorescenti. Questi metodi si prestano pure a essere automatizzati e sono quindi piu' convenienti, in termini di tempi e di costi, rispetto a quelli tradizionali. Esiste una moltitudine di gruppi di primer predisposti da regioni amplificate a sequenza caratterizzata (SCAR) e dati di sequenze di spaziatrici interne trascritte (ITS) che sono stati pubblicati e sviluppati per identificare gli agenti patogeni delle piante. Comunque, solo un numero limitato di questi e' stato applicato a test per l'accertamento della sanita' delle sementi. Questo puo' essere dovuto in parte a difficolta' tecniche, costi da sostenere per i diritti sulla PCR, cosi' come al tempo e all'organizzazione necessaria per la standardizzazione delle metodiche. Si anticipa che nel prossimo futuro test migliorati sviluppati a partire dai sistemi PCR/sonda, e dalla futura tecnologia dei chip a DNA, consentiranno di ridurre la quantita' dei trattamenti preventivi e di migliorare la gestione delle malattie trasmesse da seme
An examination was carried out under laboratory conditions to determine whether resveratrol, pterostilbene and mixtures of each stilbene with phoshorous acid had an inhibitory activity against some ...fungi involved in esca: Phaeoacremonium aleophilum, Phaeomoniella chlamydospora, Libertella blepharis (anamorph of Eutypa lata), Fomitiporia punctata and Stereum hirsutum. An inhibition of mycelial growth by resveratrol was not found, but there was a clear correlation between pterostilbene concentration and reduction of radial growth, confirming the antifungal activity of phytoalexin. Although phosphorous acid proved to be generally ineffective, an increase of antifungal activity of stilbene in the mixtures was observed with all fungi except F. punctata. The possible relation between fungal phenol oxidase activity and inhibition by mixtures of stilbenes and phosphorous acid was discussed
E' stato condotto un esperimento, in condizioni di laboratorio, per determinare se resveratrolo, pterostilbene e miscele di ogni stilbene con acido fosforoso avevano un'azione inibitoria nei confronti di alcuni funghi coinvolti nel mal dell'esca: Phaeoacremonium aleophilum, Phaeomoniella chlamydospora, Libertella blepharis (anamorfo di Eutypa lata), Fomitiporia punctata e Stereum hirsutum. Non e' stata riscontrata un'inibizione della crescita del micelio da parte del resveratrolo, ma si evidenziava una chiara correlazione fra concentrazione di pterostilbene e riduzione della crescita radiale, confermando l'attivita' antifungina della fitoalessina. Sebbene l'acido fosforoso si sia dimostrato in generale inefficace, si osservava un aumento dell'attivita' antifungina dello stilbene nelle miscele nei confronti di tutti i funghi, eccetto F. punctata. E' stato discusso il possibile rapporto fra attivita' della fenol ossidasi fungina e inibizione da parte di miscele di stilbeni e acido fosforoso
Histochemical reactions of one-year-old potted micropropagated vines (rootstock 1103 Paulsen) to inoculation with Phaeomoniella chlamydospora were studied. Microscopic examination of the vine wood ...showed that the fungus spread through the wood tissue, albeit slowly. Starting from the roots, nine months were required to colonise the first 20-25 cm of the grapevine stems. The slow spread of P. chlamydospora is thought to be due to the defence response initiated by the vines: production of tyloses, including accumulation of phenols in the vessels and adjacent tissue, and the deposition of unidentified defence-response substances, probably stilbene-like substances, from the cell walls surrounding the infection
Sono state studiate le reazioni istochimiche di viti micropropagate (portinnesto 1103 Paulsen) dell'eta' di un anno, allevate in vaso, all'inoculazione con Phaeomoniella chlamydospora. L'esame microscopico del legno di vite ha evidenziato che il fungo si diffonde attraverso il tessuto del legno, sebbene lentamente. Partendo dalle radici, erano richiesti nove mesi per colonizzare i primi 20-25 cm dei fusti delle viti. Si ritiene che la diffusione lenta di P. chlamydospora sia dovuta alla risposta di difesa iniziata dalle viti: produzione di tille, compreso l'accumulo di fenoli nei vasi e nel tessuto adiacente, e deposizione di sostanze proprie della risposta di difesa non identificate, probabilmente sostanze simili allo stilbene, da parte delle pareti cellulari circondanti l'infezione
A method was developed to monitor the formation of zoospores of Phytophthora species in the soil around potted host plants grown under greenhouse conditions. Inoculum of the pathogen was grown in ...vermiculite amended with hemp seed extract for 4 weeks at room temperature and 10 ml were placed around each plant. Pots were periodically flooded with water overnight with the drainage hole closed. Water was drained and collected next day and baited with citrus leaf discs for 48 h at room temperature and plated on a Phytophthora selective antibiotic medium. Baits colonized by Phytophthora were good indicators of the pathogen activity in the root zone of susceptible and resistant hosts
È stato sviluppato un metodo per controllare la formazione di zoospore di specie di Phytophthora nella rizosfera di piante ospiti allevate in vaso in condizioni di serra. L´inoculo del patogeno è stato sviluppato in vermiculite integrata con estratto di seme di canapa per 4 settimane a temperatura ambiente e sono stati distribuiti 10 ml dello stesso intorno a ogni pianta. I vasi sono stati periodicamente irrigati durante la notte con il foro di drenaggio chiuso. L´acqua veniva raccolta il giorno successivo e incubata con dischi di foglie di agrumi per 48 h a temperatura ambiente, successivamente posti in piastre contenenti un substrato con antibiotico selettivo per Phytophthora. I dischi colonizzati da Phytophthora sono risultati buoni indicatori dell´attività del patogeno nella rizosfera di ospiti suscettibili e resistenti.
In vitro studies were conducted into the activity of 22 fungicides against Phaeomoniella chlamydospora, the cause of Petri disease. Mycelial growth of the pathogen was inhibited by the DMI ...fungicides, cyproconazole, bitertanol, tebuconazole, fenarimol, myclobutanil and prochloraz, which gave EC₅₀ values of less than 0.2 mg 1⁻¹; by the benzimidazole fungicides, benomyl, carbendazim and thiophanate methyl, which gave EC₅₀ values of less than 0.4 mg 1⁻¹; by the anilopyrimidines, pyrimethanil and cyprodinil/fludioxonil, which gave EC₅₀ values of less than 0.02 mg 1⁻¹. The same fungicides had different effects on germination of conidia. All the DMI fungicides tested were relatively ineffective with EC₅₀ values greater than 15 mg 1⁻¹ for germination. Of the benzimidazoles, only benomyl was relatively effective at reducing germination, with an EC₅₀ value of 0.09 mg 1⁻¹, whereas the anilopyrimidines, alone or combined with phenylpyrrole, were effective with EC₅₀ values of less than 0.1 mg 1⁻¹. Kresoxim-methyl, which is locally systemic, was effective at inhibiting mycelial growth and germination with EC₅₀ values of 0.086 and 0.11 mg 1⁻¹ respectively. Of the contact fungicides tested, most were effective at reducing germination of P. chlamydospora conidia, since their EC₅₀ values were much lower than the recommended field rates, but these fungicides were also much less effective at reducing mycelial growth, for which their EC₅₀ values were up to 400 times greater. The disinfectant, hydroxyquinolene sulphate was highly effective at reducing germination but less effective against mycelial growth, with EC₅₀ values of 0.002 and 8.5 mg 1⁻¹ respectively. The potential role of these fungicides for disease management in the nursery and vineyard is discussed.
Several classical approaches have been developed to detect and identify soil fungal inhabitants through the years. Selective media have been devised to exclude the large number of soil organisms and ...allow growth or target fungi. However, the advent of molecular biology has offered a number of revolutionary insights into the detection and enumeration of soilborne fungal pathogens and also has started to provide information on the identification of unknown species from DNA sequences. This review paper focuses on the application of various molecular techniques in the detection, identification, characterization and quantification of soilborne fungal plant pathogens. This is based on information from the literature and is combined with personal research findings of the Author
Nel corso degli anni sono stati sviluppati numerosi approcci classici per individuare e identificare i funghi terricoli. Sono stati individuati substrati selettivi per escludere la gran parte degli organismi del suolo e consentire la crescita dei funghi specificamente interessanti. Tuttavia, lo sviluppo della biologia molecolare ha offerto un numero di strumenti di indagine rivoluzionari per l´individuazione e l´enumerazione dei patogeni fungini trasmessi dal terreno e ha pure iniziato a fornire informazioni sull´identificazione di specie ignote tramite le sequenze del DNA. Questa rassegna tratta dell´applicazione delle varie tecniche molecolari nell´individuazione, identificazione, caratterizzazione e quantificazione dei patogeni fungini delle piante trasmessi dal terreno. La rassegna è basata su informazioni derivate dalla letteratura, combinate con risultati delle ricerche condotte dall´Autore.
