Rapid identification of Erwinia amylovora and Pseudomonas syringae species and characterization of E. amylovora streptomycin resistance using quantitative PCR assays

2019 ◽  
Vol 65 (7) ◽  
pp. 496-509 ◽  
Author(s):  
Martin Laforest ◽  
Katherine Bisaillon ◽  
Marie Ciotola ◽  
Mélanie Cadieux ◽  
Pierre-Olivier Hébert ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Erwinia Amylovora ◽  
Control Method ◽  
Fruit Production ◽  
Effective Control ◽  
Control Methods ◽  
Bacterial Isolates ◽  
Pome Fruit ◽  
Molecular Tests

Erwinia amylovora and Pseudomonas syringae are bacterial phytopathogens responsible for considerable yield losses in commercial pome fruit production. The pathogens, if left untreated, can compromise tree health and economically impact entire commercial fruit productions. Historically, the choice of effective control methods has been limited. The use of antibiotics was proposed as an effective control method. The identification of these pathogens and screening for the presence of antibiotic resistance is paramount in the adoption and implementation of disease control methods. Molecular tests have been developed and accepted for identification and characterization of these disease-causing organisms. We improved existing molecular tests by developing methods that are equal or superior in robustness for identifying E. amylovora or P. syringae while being faster to execute. In addition, the real-time PCR-based detection method for E. amylovora provided complementary information on the susceptibility or resistance to streptomycin of individual isolates. Finally, we describe a methodology and results that compare the aggressiveness of the different bacterial isolates on four apple cultivars. We show that bacterial isolates exhibit different behaviors when brought into contact with various apple varieties and that the hierarchical clustering of symptom severity indicates a population structure, suggesting a genetic basis for host cultivar specificity.

Research on Multi-Actuators Speed Control Methods in Large-Scale Vessel

2009 ◽  
Vol 419-420 ◽  
pp. 85-88
Author(s):  
Hui Xiong Wan ◽  
Hui Huang ◽  
Hai Bo Huang
Keyword(s):  
Large Scale ◽  
Control Method ◽  
Flow Distribution ◽  
Speed Control ◽  
Effective Control ◽  
Control Methods ◽  
Simulation Research ◽  
Compensation Control ◽  
Speed Error ◽  
Pressure Compensation

For multi-actuators speed control system driven by single pump, several effective control methods have been proposed, such as flow feedback control, etc. These methods are effective only to the engineering equipment with fewer actuators. As for large vessels with more than ten actuators required for speed control, using traditional control methods will result in that costs much, the structure of the hydraulic system is very complicated, even unable to realize. In order to meet the coordinate action of many actuators, two ways based on throttle control and pressure compensation control are introduced in this paper. The research results based on the theoretical analysis of speed control error and adaptability, simulation research and experimental confirmation indicate that the throttle control method is limited by the number of actuators, load size and the speed error, but the pressure compensation control method is helpful to enhance rationality and the coordination of flow distribution between various actuators.

scholarly journals Pest Management Challenges and Control Practices in Codling Moth: A Review

Insects ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 38 ◽  
Author(s):  
Martina Kadoić Balaško ◽  
Renata Bažok ◽  
Katarina M. Mikac ◽  
Darija Lemic ◽  
Ivana Pajač Živković
Keyword(s):  
Insecticide Resistance ◽  
Insect Pest ◽  
Cydia Pomonella ◽  
Genetic Research ◽  
Codling Moth ◽  
Fruit Production ◽  
Control Measures ◽  
Effective Control ◽  
Pome Fruit ◽  
Proactive Management

The codling moth, Cydia pomonella L., is a serious insect pest in pome fruit production worldwide with a preference for apple. The pest is known for having developed resistance to several chemical groups of insecticides, making its control difficult. The control and management of the codling moth is often hindered by a lack of understanding about its biology and ecology, including aspects of its population genetics. This review summarizes the information about the origin and biology of the codling moth, describes the mechanisms of resistance in this pest, and provides an overview of current research of resistant pest populations and genetic research both in Europe and globally. The main focus of this review is on non-pesticide control measures and anti-resistance strategies which help to reduce the number of chemical pesticides used and their residues on food and the local environment. Regular monitoring for insecticide resistance is essential for proactive management to mitigate potential insecticide resistance. Here we describe techniques for the detection of resistant variants and possibilities for monitoring resistance populations. Also, we present our present work on developing new methods to maintain effective control using appropriate integrated resistance management (IRM) strategies for this economically important perennial pest.

Studies on the Quality Control of Low-Sugar Preserved Kiwifruit

2011 ◽  
Vol 268-270 ◽  
pp. 16-19
Author(s):  
Kai Sheng Zhang ◽  
Jiao She
Keyword(s):  
Quality Control ◽  
Control Method ◽  
Fruit Production ◽  
Control Technique ◽  
Control Methods ◽  
Key Factors ◽  
Preserved Fruit ◽  
The Comparative Study ◽  
Technical Basis

Analysis of low-sugar preserved Kiwifruit processing status and the key factors of quality control, based on the comparative study of different control methods, fuzzy control technique is applied to the quality control of low-sugar preserved Kiwifruit with using the embedded microcontroller processor to design the system controlling hardware, and the system software flowchart. The control studies of the end product quality of the low-sugar preserved Kiwifruit can provide the technical basis and process control method for low-sugar food-preserved fruit production process , so the corresponding products satisfy the people's low-sugar and low-calorie requirements.

scholarly journals Tracking the dissemination of Erwinia amylovora in the Eurasian continent using a PCR targeted on the duplication of a single CRISPR spacer

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Mirjam Kurz ◽  
Simon Carnal ◽  
Mery Dafny-Yelin ◽  
Orly Mairesse ◽  
Richard A. Gottsberger ◽  
...  
Keyword(s):  
Western Europe ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Eastern Mediterranean ◽  
Epidemiological Studies ◽  
Fruit Production ◽  
Pome Fruit ◽  
Hypervariable Regions ◽  
Phylogenetic Studies ◽  
Eurasian Continent

AbstractFire blight is the most devastating disease affecting pome fruit production globally. The pathogen is native to North America and was imported to western Europe in the 1950s, progressively spreading over the continent in the ensuing decades. Previous phylogenetic studies have revealed the extreme genetic homogeneity of the pathogen outside its center of origin, which makes epidemiological studies difficult. These are generally only possible using hypervariable regions of the genome such as those represented by CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats), which are, however, not practical to sequence due to their size and variability. Here, we present a simple PCR assay targeting the duplication of a single CRISPR spacer in Erwinia amylovora that was found to be an important marker to discriminate between two main European populations of the pathogen. We implemented the assay on a total of 582 isolates to follow the spread of fire blight across the continent over several decades and, wherever possible, within single countries. The results obtained point to the occurrence of two major separate introduction events for E. amylovora in Europe that occurred approximately 20 years apart, and confirmed the existence of two principal distribution areas located in Northeastern Europe and the Eastern Mediterranean Basin from which the pathogen moved on to colonize the Eurasian continent.

scholarly journals Comparative Study Regarding in Vitro Infections with Erwinia Amylovora and Pseudomonas Syringae Pv. Syringae on Pomaceae Species

2015 ◽  
Vol 48 (1) ◽  
pp. 97-106
Author(s):  
Irina Paraschiva Chiriac ◽  
Fl. D. Lipşa ◽  
E. Ulea
Keyword(s):  
Pseudomonas Syringae ◽  
Erwinia Amylovora ◽  
Plant Protection ◽  
Fruit Trees ◽  
Pome Fruit ◽  
Occurrence Time ◽  
Major Objective ◽  
Great Economic Importance ◽  
In Vitro Inoculation

Abstract The knowledge about pome fruit trees bacterioses and their evolution in orchards is a major objective for plant protection. Erwinia amylovora and Pseudomonas syringae pv. syringae cause on attacked organs of Pomaceae species similar dieback symptoms in vegetative and flowering shoots of quince, pear and apple in spring. Both bacteria can produce disastrous diseases in orchards and are therefore of great economic importance. Biological materials represented by vegetative shoots, leaves and fruits of Pyrus spp., Malus spp., Cydonia spp. were used after isolation of different E. amylovora and Ps. syringae pv. syringae strains for in vitro infections. Results presented in this study established that for in vitro inoculation of Pomaceae species similar symptoms in case of leaves and, respectively different symptoms for vegetative shoots and fruits occurred. The occurrence time was the only difference, because Ps. syringae pv. syringae spread faster than E. amylovora. The vegetative shoots inoculated with E. amylovora, in comparison to Ps. syringae pv. syringae, were more damaged and for both bacteria the highest values for attack degree were recorded in case of pear species, followed by quince and apples, respectively.

Research on Multi-Actuators Speed Control System in Large-Scale Ship

2009 ◽  
Vol 16-19 ◽  
pp. 1138-1142
Author(s):  
Hui Xiong Wan ◽  
Hong Jie Xia ◽  
Hai Bo Huang
Keyword(s):  
Control System ◽  
Large Scale ◽  
Control Method ◽  
Flow Distribution ◽  
Speed Control ◽  
Effective Control ◽  
Control Methods ◽  
Compensation Control ◽  
Speed Control System ◽  
Pressure Compensation

For multi-actuators speed control system driven by single pump, several effective control methods have been proposed, such as flow feedback control, etc. These methods are effective only to the engineering equipment with fewer actuators. As for large ships with more than ten actuators required for speed control, using traditional control methods will result in that costs much, the structure of the hydraulic system is very complicated, even unable to realize. In order to meet the coordinate action of many actuators, two ways based on throttle control and pressure compensation control are introduced in this paper. The research results based on the theoretical analysis of speed control error and adaptability, simulation research and experimental confirmation indicate that the throttle control method is limited by the number of actuators, load size and the speed error, but the pressure compensation control method is helpful to enhance rationality and the coordination of flow distribution between various actuators.

Reduction of Flow-Induced Vibration Using Parametric Excitation

2002 ◽  
Author(s):  
Tomotsugu Tanaka ◽  
Koetsu Takano ◽  
Hiroyuki Fujiwara ◽  
Osami Matsushita
Keyword(s):  
Parametric Excitation ◽  
Control Method ◽  
Excitation Frequency ◽  
Effective Control ◽  
Suspension Bridges ◽  
Control Procedure ◽  
Control Methods ◽  
Actual Structure ◽  
Excited Vibration ◽  
Experimental Apparatus

Vibration of structures, such as suspension bridges, skyscrapers and high rises, sometimes cause people to feel anxious. These vibrations are usually induced by the fluid flow, especially vortex shedding and they grow into self-excited vibrations, which are normally accompanied by the extremely large vibration amplitude. In order to solve these vibration problems, many researchers have reported the effectiveness of vibration control methods and most of the methods are very practical for the actual structure. These control methods usually consist of feedback control systems for the active control and some kinds of damper for the passive control. This paper deals with one control method, which is using the parametric excitation. The efficiencies of this method for the self-excited vibration have already been analytically examined by Tondl. However, it is not confirmed experimentally, and it is necessary to discuss the possibility of realization and application for the actual system. In this study, our experiment confirms the effectiveness of this control method. For this purpose, an experimental apparatus, which expressed a two degrees of freedom system and consisted of an electromagnetic actuator, a steel beam and two masses, were prepared. A digital signal processor was used for the realization of the parametric excitation control. During the experiments, we confirmed the effectiveness of the control procedure and accuracy of the theoretical results. In addition, the relationships between the ratio of the two masses and the ratio of the natural and the parametric excitation frequency, which are required for the effective control, were cleared. According to this study, the quenching of self-excited vibration by using the parametric excitation is realized within the very narrow band of frequency and the mass ratio should be small.

Research and Simulation of ABS Control Method

2015 ◽  
Vol 733 ◽  
pp. 749-753 ◽  
Author(s):  
Wei Zhang ◽  
Guan Neng Xu ◽  
Xue Xun Guo ◽  
Wen Zhang
Keyword(s):  
Fuzzy Control ◽  
Pid Control ◽  
Control Method ◽  
Point Of View ◽  
Effective Control ◽  
Control Methods ◽  
Slip Ratio ◽  
Ratio Curve ◽  
Braking Distance ◽  
Set Up

Based on the ABS model of a single wheel system, the traditional logic threshold, PID and fuzzy control method have been used to study the control system of commercial vehicle’s ABS. As the most important task of commercial vehicle’s ABS is to prevent the two front (steering) wheels from locking, the slip ratio should be controlled strictly in the safe range. A very short time of locking may cause the failure of steering, so control method which can keep slip ratio in the secure scope accurately can help vehicle avoid the danger of runaway. Set up the model on Simulink platform. Then, use the three control methods to control the ABS. By comparing and analyzing the processes and results under the control methods, find an appropriate way that can provide the most secure and effective control. From the perspective of processes (slip ratio changes), the simulations under the three control methods show the PID control gives the best slip ratio curve. The curve is almost coinciding with the ideal slip ratio curve. The oscillation of slip ratio given by fuzzy control is the most sever. From the point of view of the results (braking distance), the braking system with PID control has the shortest braking distance while with the fuzzy control has the longest. That is not to say fuzzy control is not advanced but the actual experiences difficult to get. And with the long response time, the fuzzy control is not suitable for commercial vehicle’s ABS. As a result and with the development and decreasing cost of PID controller, it is competitive in today’s ABS market.

Interactions between Two Biological Control Agents and an Herbicide for Canada Thistle (Cirsium arvense) Suppression

2011 ◽  
Vol 4 (1) ◽  
pp. 151-158 ◽  
Author(s):  
Joanna K. Sciegienka ◽  
Elai N. Keren ◽  
Fabian D. Menalled
Keyword(s):  
Biological Control ◽  
Pseudomonas Syringae ◽  
Control Method ◽  
Management Program ◽  
Cirsium Arvense ◽  
Shoot Biomass ◽  
Control Methods ◽  
Biological Control Agents ◽  
Canada Thistle ◽  
Shoot Number

AbstractWe investigated the single and combined effects of two biological control agents, the stem-mining weevilHadroplontus lituraand the pathogenPseudomonas syringaepv.tagetis, with a herbicide (reduced or full application of glyphosate: 0.63 kg ae ha−1, or 3.78 kg ae ha−1, respectively) on the growth of Canada thistle,Cirsium arvense. We hypothesized that first, although each control method would have a negative effect on Canada thistle shoot biomass, root biomass, and shoot number, the integration of more than one control method would have greater impact than individual control methods. Second, we hypothesized that the order in which control methods are applied affects the outcome of the management program, with a pathogen application following weevil infestation being more effective than one prior to it. Although control methods impacted Canada thistle growth (P < 0.001, expect for a nonsignificant impact of glyphosate on shoot number), the combined effect of the three control methods behaved, generally, in an additive manner. A marginal interaction between the pathogen and the herbicide (P = 0.052) indicated a slight antagonistic interaction between these control methods. An interaction between the two biological control agents tested (P < 0.001) indicated that application of a pathogen prior to the release of weevil larvae could be more deleterious to Canada thistle than a late application. The observed, mostly additive, relationship between biological control agents and herbicides implies that integrating control methods rather than using a single approach could lead to greater Canada thistle control.

scholarly journals Phenotypic and marker-assisted characterization of new apple genotypes with high resistance to fire blight

2021 ◽  
Author(s):  
Piotr Sobiczewski ◽  
Sylwia Keller-Przybyłkowicz ◽  
Mariusz Lewandowski ◽  
Artur Mikiciński ◽  
Robert Maciorowski
Keyword(s):  
Genetic Markers ◽  
High Resistance ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Disease Incidence ◽  
Region Of Interest ◽  
Breeding Programs ◽  
Molecular Tests ◽  
The Cross

AbstractIn the period 2016–2018 the susceptibility to fire blight of seven apple genotypes, including four recently bred was assessed. The studies showed that two of the genotypes (J-2003-05 and ‘Early Szampion’) are highly resistant to the disease. The indicator of assessment was evaluated by the size of necrotized part of terminal shoots after their inoculation with strain Ea659 of Erwinia amylovora. The analysis of disease incidence on individual shoots of both genotypes showed no symptoms on 92% and 100% of shoots inoculated in 2016, 83.8 and 77.0% of shoots in 2017, and 87.8 and 77.3% of shoots inoculated in 2018, respectively. Molecular tests based on 16 genetic markers revealed that genotype J-2003-05 possesses 10 resistance alleles (covering the region of interest from LG 3, 5, 7, 10 and 12). This genotype is derived from the cross between ‘Melfree’ and ‘Sawa’ and produces very large dark-red tasty fruits. Genotype ‘Early Szampion’ representing the selected hybrid from the cross of ‘Gold Milenium’ and ‘Šampion’, producing large, bright red, attractive fruits, was found to possess 10 resistance alleles (covering the region of interest from LG 3, 7, 10 and 12), Both genotypes have the prospect of being used in breeding programs and commercial planting.

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