Epidemiology of flavescence dorée in vineyards in northwestern Italy

ABSTRACT A serious outbreak of flavescence dorée (FD) was reported in Piemonte, northwestern Italy, in 1998, and since then, the disease has compromised the economy of this traditional wine-growing area, even following the application of compulsory insecticide treatments to control Scaphoideus titanus, the vector of the causal phytoplasma. Affected vines show severe symptoms, varying according to the cultivar, and are rogued to reduce disease spread. Following winter and pruning, a previously affected vine may appear symptomless and free of phytoplasmas in its aerial as well as its root system, even by nested-polymerase chain reaction assays. Such plants are considered to be "recovered". Since 1998 homogenous data on the incidence of newly infected, healthy, or recovered plants productivity, presence of vectors, and treatment schedules have been collected in seven severely affected vineyards of southern Piemonte for 5 years (1999 to 2003). Infectivity and recovery rates were also calculated each year. From 1999 to 2003, the average number of healthy plants decreased and the numbers of recovered plants and those with symptoms increased. Productivity of recovered vines, although lower than that of healthy ones, was always higher than that of vines with symptoms and was not influenced by the time elapsed from date of recovery. The relationships between the ln-transformed number of vectors trapped in the vineyards the previous year and the infection and the recovery rates were fitted by an exponential (R(2) = 0.95) and an asymptotic (R(2) = 0.93) model, respectively.     

Versuche mit Herbiziden in Waid Isatis tinctoria L. in Thüringen

Between 2002 and 2006 seven experiments with different herbicides were carried out in woad in two Thuringian experimental stations. The objective of these tests was to get the required data for the approval procedure according to the regulations of §§?18?a and?b PflSchG. The tests showed the applicability of some herbicides for the weed control in woad. Because of the possible use of woad for pharmaceutical purposes in the future investigations with dried leaves and roots of woad were carried out with the objective of getting data of the residues of active compounds in the plant materials. The results of the tests have shown that the maximum residue level for some active compounds can be exceeded. At the current situation of woad cultivation further herbicide tests in this crop are not intended.     

Versuche mit Herbiziden in Zitronenmelisse Melissa officinalis L. in Thüringen

Between 1996 and 2008 19 experiments with 33 herbicides were carried out in lemon balm in experimental stations and on lemon balm fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of §?18a PflSchG. Lemon balm plants are very susceptible against some herbicides like Bacara, Bandur, Centium 36?CS, Goltix 700?SC, Husar, Sumimax. Other herbicides like Boxer, Stomp?SC and other Pendimethalin-herbicides can cause severe damages on peppermint if they are applied to the false stage of development of the plant and/or unfavourable climatic conditions. The use oft the herbicides Basagran, Boxer, Fusilade MAX, Lentagran WP and Stomp SC, Stomp Aqua, Stomp Raps is authorized for the application in lemon balm according the regulations of §?18a PflSchG. The herbicides Goltix 700?SC, Lontrel?100 und CLIOPHAR?100, Roundup UltraMAX and Targa Super can be used in lemon balm according the regulations of §?18b PflSchG. Further experiments with herbicides in lemon balm are intended to the authorization to more herbicides and to unsolved problems with the weed control in this crop like for example the often insufficient effects of the recently authorized herbicides against Solanum spec., Galinsoga spec., Polygonum spec. and other weeds.     

Versuche mit Herbiziden in Baldrian Valeriana officinalis L. in Thüringen

Between 1998 and 2008 12 experiments with 25 herbicides were carried out in valerian in experimental stations and on valerian fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of § 18 a PflSchG. The use oft the herbicides Devrinol FL, Lentagran WP, Stomp Aqua and Stomp Raps is authorized for the application in valerian according the regulations of § 18 a PflSchG. The herbicides Basagran, Boxer, Roundup UltraMAX and Targa Super can be used in valerian according the regulations of § 18 b PflSchG. Further experiments with herbicides in valerian are intended to the authorization to more herbicides and to unsolved problems with the weed control in this crop like for example the often insufficient effects of the recently authorized herbicides against Solanum spec., Galinsoga spec., Polygonum spec. and other weeds.     

Virusnachweis in Blattläusen

Potato virus Y (PVY) causes great economic losses in potato production world-wide. Concerning important it has replaced Potato leafroll virus (PLRV). Virus is transmitted by different aphid species in a non-persistent manner. During last years the developing of new effective methods for PVY monitoring, forecasting and detection in aphids is of increasing interest. Sensitive, rapid detection of virus in its natural vectors is of a great need to investigate the relationship between aphid migration and the spread of PVY. Simple diagnostic protocol for the detection of non-persistent Plum pox virus and semipersistent Citrus tristeza virus in aphids, proposed by Olmos et al. (2005) was probed to validate and estimate the efficiency of its applying for the detection of PVY in different aphid species too.     

Versuche mit Herbiziden in Pfefferminze Mentha x piperita L. in Thüringen

Between 1996 and 2007 31 experiments with 34 herbicides were carried out in peppermint in experimental stations and on peppermint fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of §?18a PflSchG. Peppermint plants are susceptible against some herbicides like Callisto, Monitor. Other herbicides like Afalon, Basta, Boxer, Centium 36 CS and Roundup Ultra can cause severe damages on peppermint if they are applied to the false stage of development of the plant. The use oft the herbicides Basagran, Fusilade MAX, Lentagran WP, Lontrel 100 and CLIOPHAR 100 is authorized for the application in peppermint according the regulations of §?18a PflSchG. The herbicides Bandur, Boxer, Stomp SC and Targa Super can be used in peppermint according the regulations of §?18b PflSchG. Further experiments with herbicides in peppermint are intended to the authorization to more herbicides and to unsolved problems with the weed control like for example the often insufficient effects of the recently authorized herbicides against Solanum spp., Galinsoga spp., Polygonum spp. and other weeds.     

Versuche mit Herbiziden in Artischocke (Cynara scolymus L.) in Thüringen

Between 1998 and 2003 11 experiments with 24 herbicides were carried out in artichoke in experimental stations and on artichoke fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of § 18 a PflSchG. Artichoke plants are very susceptible against some herbicides like Afalon, Bandur, Cirrus, Goltix 700 SC, Oratio, Stefes IPU. Other herbicides like Lentagran WP, Stomp Aqua or Stomp Raps can cause severe damages on artichoke if they are applied on unfavourable climatic conditions. The use oft the herbicides BASTA, Devrinol Kombi CS, Gallant Super, Kontakt 320 SC, Lentagran WP, Stomp SC/Stomp Aqua and Targa Super was authorized for the application in artichoke according the regulations of § 18 a PflSchG in the past. The herbicides Fusilade MAX, Kontakt 320 SC and Roundup UltraMAX can be used in artichoke according the regulations of § 18 b PflSchG. These herbicides aren??t enough for the chemical control of weeds likeEchinochloa spec.,Galinsoga spec., Polygonum spec. in artichoke. In addition to the application of the herbicides are mechanical measures necessary.     

Resistance in leaf blades assessed by counting conidia correlates with whole-plant-specific resistance in leaf sheaths in a compatible rice–Magnaporthe oryzae interaction

Resistance in the leaf blades of rice plants against a virulent race of the rice blast fungus Magnaporthe oryzae was quantitatively examined using a modified spot inoculation method. Numbers of conidia produced in the lesions were affected by plant age and paralleled the frequency of resistance infection types, which is indicative of whole-plant-specific resistance (WPSR), in the inoculated leaf sheaths of the corresponding plants. Exogenous abscisic acid treatment, which suppresses WPSR, also increased the susceptibility of the leaf blades. These results indicate a correlation between the resistance of the leaf blades and the WPSR in the leaf sheaths.     

Seasonal variations in glacier velocity in the High Mountain Asia region during 2015–2020

Velocity is an important component of glacier dynamics and directly reflects the response of glaciers to climate change. As a result, an accurate determination of seasonal variation in glacier velocity is very important in understanding the annual variation in glacier dynamics. However, few studies of glacier velocity in the High Mountain Asia(HMA) region were done. Along these lines, in this work, based on Sentinel-1 glacier velocity data, the distribution of glacier velocity in the HMA region ...     

β-Aminobutyric Acid-induced Resistance in Plants

Thehe broad sprectrum protective effect of the non-protein amino acid -aminobutyric acid (BABA) against numerous plant diseases has been well-documented in the literature. Here, we present an overview of BABA-induced protection in various pathosystems. Contriidictory reports concerning the mechanism of action underlying this type of protection incited us to take advantage of Arabidopsis/pathogen interactions as model systems to investigate the action of BABA at the genetic and molecular level. We present evidence that the protective effect of BABA is due to a potentiation of natural defense mechanisms against biotic and abiotic stresses. In order to dissect the pathways involved in potentiation by BABA describe the use of a mutational approach based on BABA-induced female sterility in Arabidopsis.     

Hausrattennachweise (Rattus rattus L.) in bewohnten Wohnh?usern in Magdeburg

Storehouses and mills in the Magdeburg region are known to be infested with black (ore house) rats. In residential buildings, however, house rats (Rattus rattus L.) have not been detected for at least 20 years. Therefore, it was of much interest for the expert to note that this rat species had been seen in two occupied residential buildings (a refurbished old building and a terraced house). It has been suspected for a longer time that black rats can be found in certain residential buildings in towns or even cities.     

Characterization of Populations of Rhizoctonia solani in Paddy Rice Fields in Côte d'Ivoire

ABSTRACT Isolates of Rhizoctonia solani were obtained from plant and soil samples that had been systematically collected in a field experiment in C?te d'Ivoire to study the diversity of the pathogen and the influence of three different rice rotations on the pathogen population. Characterization by morphology, anastomosis testing, pathogenicity testing, and restriction fragment length polymorphisms (RFLPs) of AT-rich DNA (AT-DNA) showed that there were no differences in isolates from different experimental plots, suggesting that the soil as well as the plant population of the fungus was indistinguishable throughout the experiment and was not influenced by crop rotation. Analysis of AT-DNA showed that the isolates obtained from plant material and one from soil shared a distinct banding pattern, identical with the AT-DNA RFLP obtained for the reference strain of anastomosis group 1 (AG-1). The remaining soil isolates produced a consistent RFLP pattern that was distinct from that of the plant isolates. Morphological characterization of isolates produced two major clusters consisting of the same groups of isolates as found by AT-DNA RFLP. Diversity in morphological characters was much higher in plant than in soil isolates and indicated that the population might consist of several clones. Anastomosis testing revealed that soil as well as plant isolates were able to fuse with the tester strain of AG-1. Significant differences in disease severity were observed between the two groups of isolates in pathogenicity tests on rice plants, with plant isolates being distinctively more virulent.     

Variation of soil physical-chemical characteristics in salt-affected soil in the Qarhan Salt Lake,Qaidam Basin

Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na⁺,K⁺,and Cl^-.Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na⁺,K⁺,Ca2+,Mg²⁺,Cl^-,CO₃^2-,SO₄^2-,and HCO₃^-)were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.     

Beet necrotic yellow vein virus genome reassortments in a resistant sugar beet variety showing–in a small area in France–strong rhizomania symptoms

Journal of Plant Diseases and Protection - The genome composition of Beet necrotic yellow vein virus (BNYVV) was analysed in rootlets of field-grown sugar beets belonging to a variety which in...     

Correction to: Haplotypes of ‘Candidatus Liberibacter solanacearum’ identified in Umbeliferous crops in Spain

European Journal of Plant Pathology -     

Widespread occurrence of “Candidatus liberibacter africanus subspecies capensis” in Calodendrum capense in South Africa

Recent studies in citrus orchards confirmed that Citrus Greening, a heat sensitive citrus disease, similar to Huanglongbing (HLB), is associated with the presence of ??Candidatus Liberibacter africanus?? (Laf) in South Africa. Neither ??Candidatus Liberibacter asiaticus?? (Las), associated with HLB, ??Candidatus Liberibacter americanus??, nor ??Candidatus Liberibacter africanus ssp. capensis?? (LafC), previously detected in the Western Cape, South Africa on an indigenous Rutaceous species, Calodendrum capense (L. f.) Thunb. (Cape Chestnut), were detected in citrus. The current study aims to determine the potential role of C. capense in the epidemiology of Citrus Greening in South Africa and whether LafC poses a risk to citriculture. A total of 278?C. capense samples were collected throughout South Africa and tested for Liberibacters using real-time PCR. While LafC was found in 100 samples, distributed from all areas where collected, no evidence of Laf infection in any sample was found . The identity of the LafC present was confirmed by sequencing the amplicon derived from conventional PCR of the ?-operon of the ribosomal protein gene region of the first 17 infected trees found and of a representative sample from each district. The Liberibacter status of 44?C. capense and 272 citrus (Midnight Valencia) trees growing in close proximity to each other for over 15?years was determined. Out of 44?C. capense specimens, 43 were infected with LafC, but none of the citrus trees were infected with LafC. Based on the results of this it appears that natural spread of LafC to citrus does not occur.     

Efficacy and dose–response relationship in biocontrol of Fusarium disease in maize by Streptomyces spp.

Two isolates of Streptomyces spp. DAUFPE 11470 and DAUFPE 14632 were evaluated to determine the antagonist–pathogen inoculum concentration relationship under greenhouse conditions. Pathogen and antagonist concentration, significantly (P < 0.05) affected development of Fusarium disease in maize with a significant interaction between pathogen and antagonist concentration. Dose–response relationship also differed significantly (P < 0.05) between the two isolates, but both isolates demonstrated effective control of Fusarium disease, regardless of pathogen concentration. The isolate DAUFPE 11470 provided the most effective control. The lowest value for disease incidence occurred at low pathogen (10³ chlamydospore g⁻¹ soil) and high antagonist concentration (10⁶ cfu ml⁻¹) for both isolates. The disease incidence for control plants ranged from 19% to 76%. However, in relation to control the lowest disease reduction occurred at low pathogen (10³ chlamydospore g⁻¹ soil) and high antagonist concentrations (10⁶ cfu ml⁻¹). These reductions were 10.6% and 13% for DAUFPE 14632 and DAUFPE 11470, respectively. The highest disease reductions, in relation to control plants, occurred at high pathogen (10⁶ chlamydospore g⁻¹ soil) and antagonist (10⁶ cfu ml⁻¹) concentrations for both isolates. These values were 55% and 62.2% for DAUFPE 14632 and DAUFPE 11470, respectively. The chlamydospore germination of Fusarium moniliforme was affected by glucose addition, antagonist isolates and type of inoculum. The lowest chlamydospore germination was observed with bacterial suspensions of the isolates, for all glucose additions. The results suggested that both Streptomyces spp. isolates were effective at different doses as biocontrol agents against F. moniliforme. Also, there was evidence for at least two mechanisms of biocontrol and that apparently, both isolates showed the same mechanisms of biocontrol action related to production of bioactive compounds and competition for carbon. Further studies will be developed to improve the level and effectiveness of control by these isolates.     

Wirtschaftlichkeitsbewertung von Pflanzenschutzstrategien in E- und A‑Weizen anhand eines Feldversuches in Brandenburg mit sechsgliedriger Fruchtfolge in den Jahren 2004 bis 2016

Plant protection strategies are mostly assessed with respect to their efficacy and yield stability rather than their economic result. Therefore, this study aimed at evaluating the economic excellence of different strategies. Based on a long term field trial, the economics of four plant protection strategies in two different winter wheat quality classes (A wheat and E wheat) were evaluated. The field trial located in Dahnsdorf in Brandenburg comprised a crop rotation with six rotation components which is rather untypical for agricultural practice in that region. The economic analysis was based on field trial data from 13 years between 2004 and 2016 which was supplemented by secondary statistical data. Four plant protection strategies were considered: (S1) harrowing without chemical plant protection, (S2) plant protection in accordance to good farming practice taking into account the general principles of integrated pest management and a reduction of the treatment frequency index by (S3) 25% or rather (S4) 50% compared to good farming practice. By calculating the plant protection and labor cost free revenues for each year and strategy and by transferring these into annuities the four plant protection strategies were compared economically. The results for E wheat (elite wheat) were similar to those of A wheat (quality wheat) in terms of economic performance. A comparison of the plant protection strategies showed, that the abandonment of pesticides (S1) led to considerable economic disadvantages compared to the other three strategies. These three strategies which included the application of pesticides (S2, S3, S4) led to almost equivalent revenues, however, a reduction of the treatment frequency index by 25% compared to the good farming practice resulted in the best economical outcome for both wheat qualities. The applied crop rotation with six rotation components in combination with an intensive monitoring of the plant pests clearly supported the reduction of pesticide use in winter wheat without economic disadvantages. The results suggest, that such crop rotations have the potential to contribute to a sustainable crop production.