00427nas a2200097 4500008004100000020001800041245006600059210006600125100004500191856009300236 1999 eng d a0 642 24863 300aEnvironment Protection and Biodiversity Conservation Act 19990 aEnvironment Protection and Biodiversity Conservation Act 19991 aAustralian Department of the Environment uhttp://www.environment.gov.au/biodiversity/invasive/diseases/phytophthora-cinnamomi.html01249nas a2200169 4500008004100000022001400041245007500055210006900130260002900199300001400228490000700242520072300249100001700972700001500989700001801004856005701022 1993 eng d a1365-305900aEvidence for Phytophthora cinnamomi involvement in Iberian oak decline0 aEvidence for Phytophthora cinnamomi involvement in Iberian oak d bBlackwell Publishing Ltd a140–1450 v423 a
Rapid and sometimes extensive mortality and decline of oak, principally Quercus suber and Q. ilex, has occurred in parts of southern Spain and Portugal in recent decades. We report here isolation of the aggressive root pathogen Phytophthora cinnamomi from roots of diseased oaks or from soil at eleven out of thirteen decline foci examined. It is proposed that the introduction and spread of P. cinnamomi may be a major factor in the Iberian oak decline, interacting with drought and other site factors, and leading to stress-related attacks by insects and other fungi. By analogy, it may also be involved in the similar oak declines occurring elsewhere on the Mediterranean.
1 aBrasier, C M1 aRobredo, F1 aFerraz, J F P uhttp://dx.doi.org/10.1111/j.1365-3059.1993.tb01482.x00507nas a2200157 4500008004100000245009000041210006900131300001300200490000700213100001800220700001300238700001500251700001900266700001600285856004800301 2006 eng d00aEffect of temperature and bacteria on sporulation of Phytophthora alni in river water0 aEffect of temperature and bacteria on sporulation of Phytophthor a873–800 v711 aChandelier, A1 aAbras, S1 aLaurent, F1 aDebruxelles, N1 aCavelier, M uhttp://www.ncbi.nlm.nih.gov/pubmed/1739083402656nas a2200289 4500008004100000022001400041245008900055210006900144260002900213300001400242490000700256520181900263653002002082653001302102653001502115653002702130653001402157653001602171100002102187700001902208700001802227700001602245700002202261700001202283700001602295856005502311 2010 eng d a1365-305900aEffect of host factors on the susceptibility of Rhododendron to Phytophthora ramorum0 aEffect of host factors on the susceptibility of Rhododendron to bBlackwell Publishing Ltd a301–3120 v593 aPhytophthora ramorum causes sudden oak death (SOD) in western coastal forests of the USA. In Europe, the pathogen is mainly present in the nursery industry, particularly on Rhododendron. Because of the primary role of Rhododendron as a host and potentially as a vector, the effect of Rhododendron host factors on P. ramorum susceptibility and sporulation was investigated. Inoculation methods using either wounded or non-wounded detached leaves were applied to 59 Rhododendron cultivars and 22 botanical species, replicated in three separate years. All Rhododendron species and cultivars were susceptible when using wounded leaves, but not when using non-wounded leaves, suggesting a resistance mechanism operating at the level of leaf penetration. Using a regression tree analysis, the cultivars and species were split into four susceptibility classes. Young leaves were more susceptible than mature leaves when wounded, but less susceptible when non-wounded. This effect was not correlated with leaf hydrophobicity or the number of leaf hairs. The presence or the type of rootstock did not affect the cultivar susceptibility level. Sporangia and chlamydospore production in the leaf lesions varied widely among Rhododendron cultivars and was not correlated with the susceptibility level. The susceptibility to P. ramorum correlated well with the susceptibility to P. citricola and P. hedraiandra × cactorum, suggesting that the resistance mechanisms against these species are non-specific. Susceptibility to P. kernoviae was low for most cultivars. These findings have implications for detection, spread and disease control, and are therefore important in pest risk assessment.
10ahost resistance10aleaf age10aleaf hairs10aPhytophthora kernoviae10arootstock10asporulation1 aDe Dobbelaere, I1 aVercauteren, A1 aSpeybroeck, N1 aBerkvens, D1 aVan Bockstaele, E1 aMaes, M1 aHeungens, K uhttp://dx.doi.org/10.1111/j.1365-3059.2009.02212.x02365nas a2200289 4500008004100000022001400041245014300055210006900198260002900267300001400296490000800310520143500318653002001753653001601773653002501789653002201814653001501836653002501851653001801876100002101894700002101915700001801936700002101954700002201975700002301997856005502020 2008 eng d a1469-813700aEvidence for the role of synchronicity between host phenology and pathogen activity in the distribution of sudden oak death canker disease0 aEvidence for the role of synchronicity between host phenology an bBlackwell Publishing Ltd a505–5140 v1793 aVariations in synchronicity between colonization rate by the pathogen and host phenology may account for unexplained spatial distribution of canker disease. The hypothesis that synchronous pathogenicity and host development are necessary for incidence of sudden oak death disease was tested by correlating seasonal variations in host cambial phenology and response to inoculation with Phytophthora ramorum.
Infested container nursery beds are an important source of soilborne Phytophthora spp. for initiating disease through movement with surface water or splashing onto foliage. We investigated the effects of soil solarization, alone or with subsequent amendment with a Trichoderma asperellum biocontrol agent, on the survival of Phytophthora spp. inoculum. In field trials conducted with Phytophthora ramorum in San Rafael, CA and with P. pini in Corvallis, OR, infested rhododendron leaf inoculum was buried at 5, 15, and 30 cm below the soil surface. Solarization for 2 or 4 weeks during summer 2012 eliminated recovery of Phytophthora spp. buried at all depths in California trial 1, at 5 and 15 cm in California trial 2, but only at 5 cm in Oregon. There was no significant reduction of Phytophthora spp. recovery after T. asperellum application. Although the population densities of the introduced T. asperellum at the 5-cm depth were often two- to fourfold higher in solarized compared with nonsolarized plots, they were not significantly different (P = 0.052). Soil solarization appears to be a promising technique for disinfesting the upper layer of soil in container nurseries under certain conditions.
1 aFunahashi, F.1 aParke, J L uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-04-15-0453-RE01900nas a2200169 4500008004100000022001400041245003700055210003700092260002900129300001200158490000700170520143300177100001701610700002301627700002501650856005501675 1999 eng d a1439-032900aEtiology of oak decline in Spain0 aEtiology of oak decline in Spain bBlackwell Publishing Ltd a17–270 v293 aIn different areas of Extremadura, Western Spain, soil samples were taken at the bottom of holm oak (Quercus ilex) trees that were showing decline symptoms. Half of each sample was sterilized, and acorns were sown in both sterilized and nonsterilized soil samples. The resulting seedlings were used as baits for the isolation of fungi. Seedlings growing on the natural, nonsterilized substrate were characterized by having a lower vegetative growth than the ones growing on the sterilized soil samples, and most of them died. Phytophthora cinnnamomi was consistently isolated from their roots. Fusarium oxysporum was also isolated as well as different species of Pythium, although to a lesser extent. Pathogenicity tests were performed on holm oak seedlings with five different isolates of P. cinnamomi, with F. oxysporum, Pythium and with a mixture of the three fungi. All the inoculated seedlings with P. cinnamomi developed root rot and grew slowly, and 35.7% of them died up to the end of the experiments. P. cinnamomi was consistently isolated from their roots, indicating that this fungus is the causal agent of holm oak decline. However, F. oxysporum caused similar symptoms on oak seedlings as P. cinnamomi, and was isolated also from the roots, although its frequency was lower than that of P. cinnamomi.
1 aGallego, F J1 aPerez de Algaba, A1 aFernandez-Escobar, R uhttp://dx.doi.org/10.1046/j.1439-0329.1999.00128.x01930nas a2200229 4500008004100000022001400041245011800055210006900173260002900242300001400271490000700285520118000292653002301472653002701495653002201522653002101544653002901565100001801594700001601612700001701628856005501645 2009 eng d a1365-305900aEfficacy of phosphonic acid, metalaxyl-M and copper hydroxide against Phytophthora ramorum in vitro and in planta0 aEfficacy of phosphonic acid metalaxylM and copper hydroxide agai bBlackwell Publishing Ltd a111–1190 v583 aThe ability of metalaxyl-M, phosphonic acid in the form of phosphonate, and copper hydroxide to inhibit different stages in the life cycle of Phytophthora ramorum, the causal agent of sudden oak death (SOD), was tested in vitro using 12 isolates from the North American forest lineage. In addition, experiments were conducted in planta to study the ability of phosphonic acid injections and metalaxyl-M drenches to control pathogen growth on saplings of California coast live oak (Quercus agrifolia), and of copper hydroxide foliar sprays to control infection of California bay laurel (Umbellularia californica) leaves. Phytophthora ramorum was only moderately sensitive to phosphonic acid in vitro, but was highly sensitive to copper hydroxide. In planta experiments indicated the broad efficacy of phosphonic acid injections and of copper hydroxide sprays in preventing growth of P. ramorum in oaks and bay laurels, respectively. Finally, although metalaxyl-M was effective in vitro, drenches of potted oak trees using this active ingredient were largely ineffective in reducing the growth rate of the pathogen in planta.
10adisease management10aphenotypic variability10aQuercus agrifolia10aSudden oak death10aUmbellularia californica1 aGarbelotto, M1 aHarnik, T Y1 aSchmidt, D J uhttp://dx.doi.org/10.1111/j.1365-3059.2008.01894.x01294nas a2200181 4500008004100000022001400041245006800055210006800123300001400191490000700205520072100212100002600933700002300959700001900982700001901001700002101020856007101041 2012 eng d a0966-842X00aEmergence of the sudden oak death pathogen Phytophthora ramorum0 aEmergence of the sudden oak death pathogen Phytophthora ramorum a131 - 1380 v203 aThe recently emerged plant pathogen Phytophthora ramorum is responsible for causing the sudden oak death epidemic. This review documents the emergence of P. ramorum based on evolutionary and population genetic analyses. Currently infection by P. ramorum occurs only in Europe and North America and three clonal lineages are distinguished: EU1, NA1 and NA2. Ancient divergence of these lineages supports a scenario in which P. ramorum originated from reproductively isolated populations and underwent at least four global migration events. This recent work sheds new light on mechanisms of emergence of exotic pathogens and provides crucial insights into migration pathways.
1 aGrünwald, Niklaus, J1 aGarbelotto, Matteo1 aGoss, Erica, M1 aHeungens, Kurt1 aProspero, Simone uhttp://www.sciencedirect.com/science/article/pii/S0966842X1100227702170nas a2200205 4500008004600000245006600046210006600112300001800178490000700196520156000203100001601763700001601779700001601795700001801811700001601829700001801845700001401863700001401877856007301891 Submitted eng d 00aEpidemiology of Phytophthora ramorum in Oregon tanoak forests0 aEpidemiology of Phytophthora ramorum in Oregon tanoak forests a1133-1143(11)0 v383 aWe followed the local intensification and dispersal of Phytophthora ramorum Werres, De Cock, & Man In’t Veld in Oregon tanoak (Lithocarpus densiflorus (Hook & Arn.) Rehd.) forests from its initial detection in 2001 through 2006, coincident with a continuing eradication effort. The initial infested area included nine scattered sites below 400m elevation, close to the Pacific Ocean near Brookings, Oregon. In subsequent years, one-half of new infections were within 122m of a previous infection, and 79% of the newly detected trees occurred within 300m of a previously identified tree. Dispersal up to 4km was occasionally recorded. Initial infection occurred in the upper crowns of tanoak trees. The pathogen was recovered in rainwater collected beneath diseased tanoak trees in every month from November 2006 through October 2007. Twenty-four multilocus microsatellite genotypes were identified among 272 P. ramorum isolates collected from Curry County. Genotypic analysis provided independent estimates of time of origin of the Oregon infestation, its clustered distribution, and dispersal distances. In all sampling years, 60%-71% of the isolates belonged to the same multilocus genotype. In 2001, 12 genotypes were detected and new genotypes were identified in each of the subsequent years, but all isolates belonged to the same clonal lineage. Knowledge of local intensification of the disease and long-distance dispersal should inform both Oregon eradication efforts and national quarantine regulations.
1 aHansen, E M1 aKanaskie, A1 aProspero, S1 aMcWilliams, M1 aGoheen, E M1 aOsterbauer, N1 aReeser, P1 aSutton, W uhttp://www.nrcresearchpress.com/doi/abs/10.1139/X07-217#.UNIUO7aKS0c01645nas a2200145 4500008004100000022001400041245012300055210006900178260000900247300000800256490000700264520115200271100001801423856005801441 1990 eng d a0815-319100aEfficacy of Neutralised Phosphonic Acid (Phosphorous Acid) Against Phytophthora Palmivora Pod Rot and Canker of Cocoa.0 aEfficacy of Neutralised Phosphonic Acid Phosphorous Acid Against c1990 a1300 v193 aIn comparative trials under a wide range of environmental conditions and management inputs, injection of cocoa trees with partially pH-neutralised phosphonic acid (H3PO3) gave similar, or better, control of pod rot caused by Phytophthora palmivora to that obtained with metalaxyl/cuprous oxide pod sprays. lnjection reduced canker incidence by up to 90% at some sites. Foliar sprays of phosphonic acid had little effect on yield or pod rot incidence at rates up to 24 g a.i./tree/application. Studies to determine the optimum dose and frequency of injection have shown a clear benefit of treatment, with both increased yields and reduced pod rot incidence, but no yield advantage was obtained through high dose rates. Alginate gel paints and direct root uptake were evaluated as alternative application methods, but were less effective than injection. H3PO3 was ineffective against vascular-streak dieback disease of cocoa, caused by Oncobasidium theobromae.
1 aHolderness, M uhttp://link.springer.com/article/10.1071%2FAPP990013002188nas a2200145 4500008004100000022001300041245007600054210006900130260000900199300000900208490000700217520168800224100001701912856011301929 1987 eng d a0031949X00aEnhancing detection of Phytophthora cactorum in naturally infested soil0 aEnhancing detection of Phytophthora cactorum in naturally infest c1987 a14750 v773 aReliable methods were needed to detect P. cactorum, one of the primary causal agents of P. crown rot of apple trees, in its natural soil environment. Apple or pear fruits, used in a baiting bioassay, were ineffective at detecting P. cactorum in naturally infested soil. Apple seedlings, cotyledons and seedling leaf pieces were successful baits, but cotyledons were the most sensitive and efficient. Completely air drying soil subsamples and then remoistening them for several days before flooding and adding plant tissue baits (extended baiting procedure) greatly enhanced detection when compared with the standard direct baiting procedure without prior manipulation of soil moisture. Bioassay incubation temp., volume of water added to remoisten air-dried soil subsamples, and incubation period following remoistening all affected detection, but the photoperiod during incubation did not. The advantages of an extended baiting bioassay with apple cotyledons were: greater sensitivity than with pear or apple fruits or by direct baiting, readily available and inexpensive baits, formation of sporangia of P. cactorum directly on necrotic cotyledons, and lack of interference by contaminating Pythium species. Cotyledons were also colonized by zoospores of P. cambivora, P. citricola and P. cryptogea, but not by those of P. megasperma, P. syringae, P. drechsleri, or an unidentified Phytophthora sp. The extended bioassay procedure routinely has provided a relatively rapid and efficient means of detecting P. cactorum in a diversity of soils within and around New York apple orchards.
1 aJeffers, S N uhttps://forestphytophthoras.org/references/enhancing-detection-phytophthora-cactorum-naturally-infested-soil02234nas a2200217 4500008004100000022001400041245013700055210006900192260002900261300001600290490000700306520151900313653002001832653002801852653002401880653001401904100001201918700001701930700001401947856005501961 2012 eng d a1365-305900aEffect of electrical conductivity on survival of Phytophthora alni, P. kernoviae and P. ramorum in a simulated aquatic environment0 aEffect of electrical conductivity on survival of Phytophthora al bBlackwell Publishing Ltd a1179–11860 v613 aThis study investigated survival of the pathogens Phytophthora ramorum, P. alni and P. kernoviae as zoospores or sporangia in response to an important water quality parameter, electrical conductivity (EC), at its range in irrigation water reservoirs and irrigated cropping systems. Experiments with different strengths of Hoagland’s solution showed that all three pathogens survived at a broad range of EC levels for at least 3 days and were stimulated to grow and sporulate at ECs > 1·89 dS m-1. Recovery of initial populations after a 14-day exposure was over 20% for P. alni subsp. alni and P. kernoviae, and 61·3% and 130% for zoospores and sporangia of P. ramorum, respectively. Zoospore survival of these pathogens at ECs < 0·41 dS m-1 was poor, barely beyond 3 days in pure water; only 0·3% (P. alni), 2·9% (P. kernoviae) and 15·1% (P. ramorum) of the initial population survived after 14 days at EC = 0·21 dS m-1. The variation in rates of survival at different EC levels suggests that these pathogens survive better in cropping systems than in irrigation water. Containment of run-off and reduction in EC levels may therefore be non-chemical control options to reduce the risk of pathogen spread through natural waterways and irrigation systems.
10aaquatic biology10aelectrical conductivity10aquarantine pathogen10azoospores1 aKong, P1 aLea-Cox, J D1 aHong, C X uhttp://dx.doi.org/10.1111/j.1365-3059.2012.02614.x00438nas a2200133 4500008004100000022001400041245007600055210006900131260002500200300001000225490000700235100001400242856004800256 2009 eng d a1387-354700aEcological impacts of non-indigenous invasive fungi as forest pathogens0 aEcological impacts of nonindigenous invasive fungi as forest pat bSpringer Netherlands a81-960 v111 aLoo, Judy uhttp://dx.doi.org/10.1007/s10530-008-9321-302190nas a2200169 4500008004100000245012800041210006900169300001200238490000700250520161400257100001701871700001501888700001701903700001701920700001701937856006601954 2011 eng d00aEffects of fuel reduction treatments on incidence of Phytophthora species in soil of a southern Appalachian Mountain forest0 aEffects of fuel reduction treatments on incidence of Phytophthor a811-8200 v953 aThe National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic—causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.
1 aMeadows, I M1 aZwart, D C1 aJeffers, S N1 aWaldrop, T A1 aBridges, W C uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-10-050500651nas a2200181 4500008004100000245012500041210006900166300001000235490000600245100002500251700002100276700001800297700002200315700002300337700002000360700002900380856006000409 2011 eng d00aEpidemiological modeling of invasion in heterogeneous landscapes: spread of sudden oak death in California (1990–2030)0 aEpidemiological modeling of invasion in heterogeneous landscapes aart170 v21 aMeentemeyer, Ross, K1 aCunniffe, Nik, J1 aCook, Alex, R1 aFilipe, Joao, A N1 aHunter, Richard, D1 aRizzo, David, M1 aGilligan, Christopher, A uhttp://www.esajournals.org/doi/abs/10.1890/ES10-00192.101738nas a2200169 4500008004100000022001400041245015900055210006900214260001600283300001400299490000800313520111700321100002701438700002201465700001601487856006501503 2016 eng d a0191-291700aEfficacy of Biofumigation with Brassica carinata Commercial Pellets (BioFence) to Control Vegetative and Reproductive Structures of Phytophthora cinnamomi0 aEfficacy of Biofumigation with Brassica carinata Commercial Pell cJan-02-2016 a324 - 3300 v1003 aThe efficacy of biofumigation with Brassica carinata pellets (BioFence) to control vegetative and reproductive structures of Phytophthora cinnamomi was investigated in vitro at different doses and temperatures. Biofumigation was effective in inhibiting mycelial growth (culture diameter) and chlamydospore and zoospore germination, and was lethal at 24 mg of pellet per plate (approximately 0.4 mg/liter). The 50% effective concentration values showed that efficacy of B. carinata pellets in inhibiting or killing the vegetative and reproductive structures of P. cinnamomi was maximum at 15°C and decreased as temperature rose to 25°C. However, the fungicide effect was independent of the temperature. In vivo biofumigation of Quercus cerris seedlings with BioFence confirmed efficacy by reducing the inoculum density (CFU/g) of P. cinnamomi, thus protecting the host from root infection. The use of BioFence provides an alternative to synthetic pesticides to control P. cinnamomi within disease management programs in agroforestry systems.
1 aMorales-Rodríguez, C.1 aVettraino, A., M.1 aVannini, Á uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-03-15-0245-RE02273nas a2200205 4500008004100000022001400041245012300055210006900178260001600247300001600263490000800279520157300287100002301860700003001883700002201913700001701935700002601952700002401978856006502002 2016 eng d a0191-291700aEndemic and Emerging Pathogens Threatening Cork Oak Trees: Management Options for Conserving a Unique Forest Ecosystem0 aEndemic and Emerging Pathogens Threatening Cork Oak Trees Manage cJan-11-2016 a2184 - 21930 v1003 aCork oak (Quercus suber) forests are economically and culturally intertwined with the inhabitants of the Mediterranean basin and characterize its rural landscape. These forests cover over two million hectares in the western Mediterranean basin and sustain a rich biodiversity of endemisms as well as representing an important source of income derived from cork production. Currently cork oak forests are threatened by several factors including human-mediated disturbances such as poor or inappropriate management practices, adverse environmental conditions (irregular water regime with prolonged drought periods), and attacks of pathogens and pests. All these adverse factors can interact, causing a complex disease commonly known as “oak decline.” Despite the numerous investigations carried out so far, decline continues to be the main pathological problem of cork oak forests because of its complex etiology and the resulting difficulties in defining suitable control strategies. An overview of the literature indicates that several pathogenic fungi and oomycota can play a primary role in the etiology of this syndrome. Therefore, the aim of this review is to analyze the recent advances achieved regarding the bio-ecology of the endemic and emerging pathogens that threaten cork oak trees with particular emphasis on the species more directly involved in oak decline. Moreover, the effect of climate change on the host-pathogen interactions, a task fundamental for making useful decisions and managing cork oak forests properly, is considered.
1 aMoricca, Salvatore1 aLinaldeddu, Benedetto, T.1 aGinetti, Beatrice1 aScanu, Bruno1 aFranceschini, Antonio1 aRagazzi, Alessandro uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-03-16-0408-FE01864nas a2200145 4500008004100000245012800041210006900169300001400238490000700252520135900259100001201618700001401630700001701644856005701661 2009 eng d00aEffectiveness of aluminum-fosetyl in the control of early nutfall of coconut tree due to Phytophthora katsurae (Pythiaceae)0 aEffectiveness of aluminumfosetyl in the control of early nutfall a123–1330 v153 aEarly nut fall and bud rot due to Phytophthora katsurae are the most important diseases of coconut tree observed in recent years at the Assinie plantations of PALMINDUSTRIE Company, Côte d’Ivoire. Field investigations conducted in 1983 revealed a high rate of nut fall (50-70%) during the rainy season. Cutting of coconut stands with rotten buds, as a way to control the spread of Oryctes sp., allowed to assess the number of dead trees over 139 and 89 ha of land for the hybrids and Grand West cultivars, respectively. In addition to those disease control measures proposed by the Company, comparison trials were systematically carried out using 2 fungicides: aluminum-fosetyl [fosetyl] at 3 doses (3.2, 4.8 and 6.4 g of active ingredient/tree) and Ridomil [metalaxyl] at one dose (3.125 g of active ingredient/tree). These fungicide were injected into the stem of the coconut every 3 months starting from December 1984. After 3 years, the efficacy of the 3 doses of aluminium-fosetyl over Ridomil in significantly reducing nut fall, even at low rates (3.2 g of active ingredient/tree), was apparent. However, the technique still remains out of reach of most farmers because of lack of technical know-how. It appears therefore, that an improvement of the technique, so as to make it accessible to the farmers, is a necessity.
1 aPohe, J1 aDongo, BK1 aN’Goran, N uhttp://www.ajol.info/index.php/aga/article/view/163302155nas a2200169 4500008004100000245011000041210006900151260001600220520149000236100001701726700001901743700002101762700003001783700002801813700003101841856011301872 2016 eng d00aEffect of Brassica Biofumigant Amendments on Different Stages of the Life Cycle of Phytophthora cinnamomi0 aEffect of Brassica Biofumigant Amendments on Different Stages of cJan-05-20163 aThe oomycete plant pathogen Phytophthora cinnamomi causes a highly destructive root rot that affects numerous hosts. Integrated management strategies are needed to control P. cinnamomi in seminatural oak rangelands. We tested how biofumigation affects crucial stages of the pathogen's life cycle in vitro, in infested soils under laboratory conditions and in planta. Different genotypes of three potential biofumigant plant species (Brassica carinata, Brassica juncea, Brassica napus) were collected at different phenological stages, analysed for their glucosinolate contents, and subsequently tested. The most effective genotypes against mycelial growth and sporangial production were further tested on the viability of chlamydospores in artificially infested natural soils and in planta on Lupinus luteus, a host highly susceptible to P.cinnamomi. Brassica carinata and B. juncea genotypes inhibited mycelial growth, decreased sporangial production, and effectively inhibited the viability of chlamydospores in soil, but only B. carinata decreased disease symptoms in plants. Effective genotypes of Brassica had high levels of the glucosinolate sinigrin. Biofumigation with Brassica plants rich in sinigrin has potential to be a suitable tool for control of oak root disease caused by P. cinnamomi in Spanish oak rangeland ecosystems.
1 aRíos, Pedro1 aObergón, Sara1 ade Haro, Antonio1 aFernández-Rebollo, Pilar1 aSerrano, María-Socorro1 aSánchez, María-Esperanza uhttp://doi.wiley.com/10.1111/jph.12482http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjph.1248202317nas a2200181 4500008004100000245011400041210006900155260001600224300001400240490000700254520173800261100002001999700001902019700002002038700002002058700001902078856003802097 2018 eng d00aEffects of temperature on germination of sporangia, infection and protein secretion by Phytophthora kernoviae0 aEffects of temperature on germination of sporangia infection and cJan-04-2018 a719 - 7280 v673 aPhytophthora kernoviae is a pathogen on a wide range of plants, but little is known of optimal infection conditions. Rhododendron ponticum leaves were inoculated with six different isolates of P. kernoviae sporangia and incubated at different temperatures from 10 to 28 °C. After 1 week, lesion development and pathogen recovery were only observed from all isolates at 15 and 20 °C and a few isolates at 10 °C. In an experiment with temperatures ranging from 20 to 25 °C, lesion development and pathogen recovery on R. ponticum, Magnolia stellata and Viburnum tinus occurred consistently at 20 and 21 °C, was limited at 22 °C, and did not occur at 23 °C and above. There was no difference in sporangia and zoospore germination at 20–25 °C. In a temperature fluctuation experiment, the necrotic area of inoculated R. ponticum leaves increased with longer incubation at 20 °C and decreased with longer incubation at 24 °C. Crude extracts of secreted proteins from P. kernoviae cultures grown at 20 and 24 °C were compared to determine any effects of temperature on pathogenicity. When spot tested on R. ponticum leaves, crude protein suspensions from cultures grown at 20 °C induced necrosis, while proteins from cultures grown at 24 °C did not. Proteomic analysis confirmed that a 10 kDa protein secreted at both 20 and 24 °C shared sequence homology to the conserved domains of known elicitins of other Phytophthora spp. The protein secreted at 20 °C that was responsible for necrosis has not been identified.
1 aShelley, B., A.1 aLuster, D., G.1 aGarrett, W., M.1 aMcMahon, M., B.1 aWidmer, T., L. uhttps://doi.org/10.1111/ppa.1278201645nas a2200157 4500008004100000245012200041210006900163260001600232300001400248490000800262520111000270100002001380700002101400700002301421856004301444 2014 eng d00aEffects of Inoculum Density and Wounding on Stem Infection of Three Eastern US Forest Species by Phytophthora ramorum0 aEffects of Inoculum Density and Wounding on Stem Infection of Th cJan-03-2014 a683 - 6890 v1623 aSeedlings of three Eastern US forest species Quercus rubra (northern red oak), Quercus prinus (chestnut oak) and Acer rubrum (red maple) were inoculated by applying Phytophthora ramorum sporangia to stems at different inoculum densities with and without wounding. Disease occurred in all treatments involving wounds, and no disease was observed in unwounded treatments. Younger seedlings (2–3 years old) did not differ significantly from older seedlings (5–6 years old) in disease incidence, but older seedlings sustained smaller lesions compared with younger seedlings. For both old and young seedlings, disease on wounded stems was observed down to the lowest sporangia concentration utilized (500 sporangia/ml for old seedlings and 100 sporangia/ml for young seedlings). The results show that in the presence of wounding, even very low sporangia concentrations can result in disease, and further suggest that wounding caused by insects and other factors may play an important role in P. ramorum epidemiology in forest environments.
1 aTooley, Paul, W1 aBrowning, Marsha1 aLeighty, Robert, M uhttp://doi.wiley.com/10.1111/jph.1225101536nas a2200169 4500008004100000022001400041245009300055210006900148260002900217300001200246520097500258653001801233653001901251100002001270700002101290856005501311 2011 eng d a1439-043400aEnhanced recovery of Phytophthora ramorum from soil following 30 Days of storage at 4°C0 aEnhanced recovery of Phytophthora ramorum from soil following 30 bBlackwell Publishing Ltd ano–no3 aChlamydospores of Phytophthora ramorum were used to infest field soil at densities ranging from 0.2 to 42 chlamydospores/cm3 soil. Recovery was determined by baiting with rhododendron leaf discs and dilution plating at time 0 and after 30 days of storage at 4°C, as recommended by USDA-APHIS. Baiting was slightly more sensitive than dilution plating in recovering P. ramorum immediately following infestation of soil and allowed detection from samples infested with as little as 0.2 chlamydospores/cm3 compared with 1 chlamydospore/cm3 for dilution plating. After 30 days of infested soil storage at 4°C, P. ramorum was detected at significantly (P = 0.05) higher levels than at time 0 with both recovery methods. The results indicate that storage of P. ramorum-infested soil at 4°C may allow for pathogen activity, such as sporangia production, which may enhance recovery from soil.
10achlamydospore10aramorum blight1 aTooley, Paul, W1 aCarras, Marie, M uhttp://dx.doi.org/10.1111/j.1439-0434.2011.01810.x02402nas a2200145 4500008004100000245011000041210006900151260001300220300001400233490000800247520192100255100002002176700002102196856003902217 2016 eng d00aThe Effect of Exposure to Decreasing Relative Humidity on the Viability of Phytophthora ramorum sporangia0 aEffect of Exposure to Decreasing Relative Humidity on the Viabil cAug 2016 a874 - 8810 v1643 aSporangia of three isolates of Phytophthora ramorum representing three different clonal lineages were subjected to relative humidity (RH) levels between 80 and 100% for exposure periods ranging from 1 to 24 h at 20°C in darkness. Plastic containers (21.5 × 14.5 × 5 cm) were used as humidity chambers with 130 ml of glycerine solution added to each container. Glycerine concentrations corresponded to 100, 95, 90, 85 and 80% RH based on refractive index measurements. Sporangia suspensions were pipeted onto nitrile mesh squares (1.5 × 1.5 cm, 15 micron pore size) which were placed in the humidity chambers and incubated at 20°C in darkness. Following exposure periods of 1, 2, 4, 8, 12 and 24 h, mesh squares were inverted onto Petri dishes of selective medium and sporangia germination assessed after 24 and 48 h. At 100% RH, we observed a mean value of 88% germination after 1 h exposure declining to 18% germination following 24 h incubation. At 95% RH, a steeper decline in germination was noted, with means ranging from 79% at 1 h to less than 1% at 24 h exposure. At 90% RH, no germination was noted after 8 or more h exposure, and values were 57%, 22% and 3% germination for the 1, 2 and 4 h exposures, respectively. Germination was only observed at 1 h exposure for both the 85% RH treatment (52% germination) and the 80% RH treatment (38% germination). The three isolates responded similarly over the range of RH values tested. The germination response of P. ramorum sporangia to RH values between 80% and 100% was comparable to that reported for other Phytophthora species. Knowledge of conditions that affect P. ramorum sporangia germination can shed light on pathogenesis and epidemic potential and lead to improved control recommendations.
1 aTooley, Paul, W1 aBrowning, Marsha uhttps://doi.org/10.1111/jph.12506 00538nas a2200121 4500008004100000245010100041210006900142260004000211300000700251490000800258100001700266856013300283 1953 eng d00aEpiphytology and etiology of a Phytophthora-induced root rot diseases of Chamaecyparis in Oregon0 aEpiphytology and etiology of a Phytophthorainduced root rot dise aCorvallis, ORbOregon State College a720 vPhD1 aTorgeson, DC uhttps://forestphytophthoras.org/references/epiphytology-and-etiology-phytophthora-induced-root-rot-diseases-chamaecyparis-oregon01785nas a2200241 4500008004100000022001400041245008400055210006900139260002600208300001400234490000700248520106700255653001901322653001801341653001801359653002401377653001901401100001901420700001701439700001701456700001501473856005501488 2003 eng d a1365-305900aEvaluation of root damage to English walnut caused by five Phytophthora species0 aEvaluation of root damage to English walnut caused by five Phyto bBlackwell Science Ltd a491–4950 v523 aThe pathogenicity of five species of Phytophthora to English walnut was studied in a greenhouse experiment. Phytophthora cinnamomi was the most aggressive species, causing severe root rot and seedling mortality. The other species tested, P. cambivora, P. citricola, P. cactorum and P. cryptogea, did not induce visible crown symptoms on seedlings 2 months after inoculation. Some strains of P. cambivora and P. cactorum also caused taproot damage to seedlings. All except one of the tested isolates caused significant necrosis of fine roots and a significant reduction of root weight compared with noninoculated seedlings. Reduction of above-ground plant development was not statistically significant. While P. cinnamomi is well known as an aggressive primary pathogen of English walnut, the other species of Phytophthora may act as predisposing factors to walnut decline, affecting root system development and increasing host vulnerability to environmental stress.
10aEnglish walnut10aJuglans regia10apathogenicity10asoilborne pathogens10awalnut decline1 aVettraino, A M1 aBelisario, A1 aMaccaroni, M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00864.x00603nas a2200133 4500008004100000245008700041210006900128260009400197300001200291100001500303700001400318700001400332856012300346 1985 eng d00aEcology, pathology and management of Port-orford Cedar (Chamaecyparis lawsoniana).0 aEcology pathology and management of Portorford Cedar Chamaecypar bUSDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. a161 pp.1 aZobel, D B1 aRoth, L F1 aHawk, G M uhttps://forestphytophthoras.org/references/ecology-pathology-and-management-port-orford-cedar-chamaecyparis-lawsoniana