scholarly journals Seed viability of common ragweed (Ambrosia artemisiifolia L.) is affected by seed origin and age, but also by testing method and laboratory

NeoBiota ◽  
2021 ◽  
Vol 70 ◽  
pp. 193-221
Author(s):  
Rea Maria Hall ◽  
Bernhard Urban ◽  
Hana Skalova ◽  
Lenka Moravcová ◽  
Ulrike Sölter ◽  
...  
Keyword(s):  
Seed Viability ◽  
Ambrosia Artemisiifolia ◽  
Testing Methods ◽  
Triphenyltetrazolium Chloride ◽  
Viability Test ◽  
Common Ragweed ◽  
Testing Procedures ◽  
Testing Method ◽  
Seed Origin ◽  
Set Up

Common ragweed (Ambrosia artemisiifolia L.) is an annual Asteraceae species native to North America which is highly invasive across Europe and has harmful impacts, especially on human health and agriculture. Besides its wide ecological range, particularly its high reproductive power by seeds is promoting its spread to various habitats and regions. To prevent further spread and to control the plant, the European Commission funded projects and COST-Actions involving scientists from all over Europe. A joint trial was set up comprising eight different laboratories from Europe to study seed viability variation in different seed samples. Three different testing methods (viability test with 2,3,5-triphenyltetrazolium chloride (TTC), a germination test combined with a subsequent TTC test and a crush test) were tested within the EU-COST-Action SMARTER network to four different seed origins. The viability test results from different laboratories were compared for variation amongst tests and laboratories. The main aim was to optimise the reliability of testing procedures, but results revealed not only significant effects of seed origin and seed age on seed viability, but also considerable differences between the output of the individual testing methods and furthermore between laboratories. Due to these significant differences in the results of the testing labs, additionally a second test was set up. Twelve Austrian ragweed populations were used for TTC testing to obtain a precise adjustment of the testing method as well as a tight guideline for interpreting the results, particularly for the TTC state “intermediate” since a proper classification of TTC-intermediate coloured seeds is still a challenge when determining viability rates.

Common ragweed (Ambrosia artemisiifolia) seed shattering in wheat, corn, and soybean

Weed Science ◽  
2020 ◽  
Vol 68 (5) ◽  
pp. 510-516
Author(s):  
Marie-Josée Simard ◽  
Robert E. Nurse ◽  
Eric R. Page ◽  
Gaétan Bourgeois
Keyword(s):  
Spring Wheat ◽  
Seed Viability ◽  
Ambrosia Artemisiifolia ◽  
Weather Data ◽  
Eastern Canada ◽  
Seed Shattering ◽  
Common Ragweed ◽  
Late Emergence ◽  
Single Location ◽  
Seed Biomass

AbstractBefore any late-season weed control operations are planned to manage herbicide-resistant weeds, it is essential to evaluate the plants’ maturity and shattering potential. Our goal was to assess the seed-shattering phenology of common ragweed (Ambrosia artemisiifolia L.) using pollination bags as seed traps. A secondary goal was to evaluate the efficiency of these traps. Trials were conducted from 2014 to 2017 at two locations in eastern Canada (Saint-Jean-sur-Richelieu, QC, and Harrow, ON). At each location, three adjacent fields were seeded with spring wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.], or corn (Zea mays L.). Each field was divided into four replicate blocks that included two treatment plots with 5 weeds m−2 planted on the same date as the crop or when crop plants had two leaves (early or late emergence). To evaluate shattering in time, the experiment included up to 12 weekly collection dates (subplots). In each subplot, weeds were individually bagged at flowering (using mesh bags) until collection, when the number and viability of shattered and retained seeds per plant was recorded. Weather data as well as crop and weed stages were recorded. The effect of the pollen bags on seed retrieval and viability was evaluated by installing open and closed bags in corn and uncropped (bare) plots at a single location. Ambrosia artemisiifolia seed biomass was equivalent or higher in closed bags, and seed viability was equivalent or slightly reduced. No seeds were produced before harvest in spring wheat, as dispersal started in September. The percentage of seeds retained on the plant decreased linearly (1 site-year) or followed a logistic equation (4 site-years) with day of year or growing degree days. Dispersal in time was similar between early- and late-emerging weeds and similar in both corn and soybean. On average, more than 50% of A. artemisiifolia seeds were dispersed before harvest in corn and soybean.

scholarly journals Managing glyphosate-resistant common ragweed (Ambrosia artemisiifolia): effect of glyphosate-phenoxy tank mixes on growth, fecundity, and seed viability

Weed Science ◽  
2016 ◽  
Vol 65 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Jichul Bae ◽  
Robert E. Nurse ◽  
Marie-Josée Simard ◽  
Eric R. Page
Keyword(s):  
Seed Production ◽  
New Technologies ◽  
Seed Viability ◽  
Male Flower ◽  
The United States ◽  
Ambrosia Artemisiifolia ◽  
High Fecundity ◽  
Common Ragweed ◽  
Stage Of Development ◽  
Herbicide Treatments

Common ragweed is one of the most important weeds in the soybean-producing areas of the United States and Canada. Recently, glyphosate-resistant (GR) biotypes have been reported in 15 states and one Canadian province. Reducing the proliferation of GR common ragweed biotypes is complicated by the high fecundity and complex seed germination behavior exhibited by this species. An experiment was conducted to evaluate the efficacy of late herbicide applications for reducing seed production, seed weight, and seed viability of a GR common ragweed biotype. Herbicide treatments included: water control, glyphosate, 2,4-D, dicamba, 2,4-D plus glyphosate, and dicamba plus glyphosate. Treatments were applied at the appearance of male flower buds (Biologische Bundesanstalt, Bundessortenamt and Chemical industry scale [BBCH] 51) or at the early female flowering stage (BBCH 61 to 63). At BBCH 51, 2,4-D or dicamba applied alone or in a tank mix with glyphosate reduced seed production by an average of 80%. Conversely, seed production following these same treatments applied at BBCH 61 to 63 was not significantly different from when glyphosate was applied alone. At this stage of development, all herbicide treatments reduced seed viability relative to the control; however, treatments containing 2,4-D or dicamba resulted in significantly lower viability than when glyphosate was applied alone. These results suggest that the application of tank mixes containing 2,4-D or dicamba have the potential to limit seed production of GR common ragweed when applied on or before BBCH 51. The development of new technologies that facilitate the in-crop application of tank mixes containing 2,4-D or dicamba may therefore be an effective option for limiting population establishment, seedbank replenishment, and future spread of glyphosate-resistant alleles.

scholarly journals 9. Evaluation of Synergy Testing Methods for Clinical Labs to Determine Susceptibility of Extensively Drug-resistant Gram-negatives to Ceftazidime/ Avibactam and Aztreonam Combination Therapy

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S5-S6
Author(s):  
Ayesha Khan ◽  
Samuel G Erickson ◽  
Cedric H Pettaway ◽  
Cesar A Arias ◽  
William R Miller ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Clinical Decision Making ◽  
Research Study ◽  
Scientific Research ◽  
Major Error ◽  
Testing Methods ◽  
Research Support ◽  
Testing Method ◽  
Study Investigator ◽  
Synergy Testing

Abstract Background Carbapenem-resistant Enterobacterales (CRE) and Pseudomonas aeruginosa (CR-PA) producing Metallo-β-lactamases (MBLs) cause severe nosocomial infections with no defined treatment. Combination therapy with ceftazidime/ avibactam (CZA) and aztreonam (ATM) is a potential option, but there is no approved, feasible, synergy testing method for clinical labs to guide clinical decision making. Here, we evaluate the performance of 4 synergy testing methods using gradient-strips or disks. Methods We used 10 representative Enterobacterales strains, namely, E. coli, K. pneumoniae, and E. cloacea, and 6 PA strains harboring MBL, GES or non-MBL enzymes (Fig 1). 4 strains were successfully treated with CZA-ATM in case reports, the rest were from the CDC AR Bank. Four synergy testing methods were evaluated, i) Disk stack (DS), ii) Disk elution (DE), iii) Gradient-strip Stack (SS), iv) Gradient-strip Cross (SX) (Fig 1). All methods were run side-by-side as per CLSI guidelines with broth microdilution (BMD) as the reference. Data is the mean of 3 replicates. Synergy is defined as a strain that is resistant (R) to ATM but drops to ≤ the susceptible (S) breakpoint (Table 1) in the presence of CZA (Fig 2). Categorical agreement (CA), very major error (VME), major error (ME), minor error (MI) were calculated across methods for CZA-ATM synergy relative to BMD. Summary of synergy testing methods evaluated CLSI Breakpoints used for this study Results All CRE with NDM and PA with GES were ATM-R, CZA-R and S to the CZA-ATM combination. PA with NDM or VIM remained R to CZA-ATM likely due to other mechanisms of resistance. CA was high for DE (100%), SS (81%, MI 19%), and SX (88%, MI 13%) but low for DS (25%, ME 54%, MI 31%). Representative strains are shown (Fig 2, Table 2). Removing PA, CA for DE, SS, and SX was 100% and 20% for DS. Representative results of strains with each synergy testing method. Representative data of strains displaying synergy (green) or no synergy (red) Conclusion Overall, DE was the most reliable method for CZA-ATM synergy testing, and could be a valuable tool in low-resource labs. SS and SX were reliable but prone to technical error. DS had the worst performance. Disks and gradient-strips had identical performance across brands. We propose an algorithm for ATM-R, CZA-R, and MBL-positive CRE, where CZA-ATM synergy testing may be beneficial to guide therapy. These methods are reliable qualitative indicators of the presence or absence of synergy. Synergy testing is not recommended for CR-PA due to complex resistance profiles. Disclosures Cesar A. Arias, M.D., MSc, Ph.D., FIDSA, Entasis Therapeutics (Scientific Research Study Investigator)MeMed (Scientific Research Study Investigator)Merck (Grant/Research Support) William R. Miller, MD, Entasis Therapeutics (Scientific Research Study Investigator)Merck (Grant/Research Support)Shionogi (Advisor or Review Panel member)

scholarly journals Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Seed Viability ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Viability Test ◽  
Physiological Dormancy ◽  
Different Temperatures ◽  
Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

scholarly journals A high diversity of mechanisms endows ALS-inhibiting herbicide resistance in the invasive common ragweed (Ambrosia artemisiifolia L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ingvild Loubet ◽  
Laëtitia Caddoux ◽  
Séverine Fontaine ◽  
Séverine Michel ◽  
Fanny Pernin ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Resistance Management ◽  
Genotyping By Sequencing ◽  
Ambrosia Artemisiifolia ◽  
Target Site ◽  
Major Type ◽  
Common Ragweed ◽  
Resistance Evolution ◽  
Arable Weed ◽  
Target Site Resistance

AbstractAmbrosia artemisiifolia L. (common ragweed) is a globally invasive, allergenic, troublesome arable weed. ALS-inhibiting herbicides are broadly used in Europe to control ragweed in agricultural fields. Recently, ineffective treatments were reported in France. Target site resistance (TSR), the only resistance mechanism described so far for ragweed, was sought using high-throughput genotyping-by-sequencing in 213 field populations randomly sampled based on ragweed presence. Additionally, non-target site resistance (NTSR) was sought and its prevalence compared with that of TSR in 43 additional field populations where ALS inhibitor failure was reported, using herbicide sensitivity bioassay coupled with ALS gene Sanger sequencing. Resistance was identified in 46 populations and multiple, independent resistance evolution demonstrated across France. We revealed an unsuspected diversity of ALS alleles underlying resistance (9 amino-acid substitutions involved in TSR detected across 24 populations). Remarkably, NTSR was ragweed major type of resistance to ALS inhibitors. NTSR was present in 70.5% of the resistant plants and 74.1% of the fields harbouring resistance. A variety of NTSR mechanisms endowing different resistance patterns evolved across populations. Our study provides novel data on ragweed resistance to herbicides, and emphasises that local resistance management is as important as mitigating gene flow from populations where resistance has arisen.

scholarly journals Efficiency of glyphosate and ammonium glufosinate against common ragweed (Ambrosia artemisiifolia L.) in vineyards

2019 ◽  
pp. 45-50
Author(s):  
A. S. Golubev ◽  
I. P. Borushko ◽  
V. I. Dolzhenko
Keyword(s):  
Quantitative Method ◽  
Application Rate ◽  
Ambrosia Artemisiifolia ◽  
Cabernet Sauvignon ◽  
Weed Species ◽  
Common Ragweed ◽  
Glufosinate Ammonium ◽  
Ammonium Glufosinate ◽  
Effi Ciency ◽  
Krasnodar Region

The use of glyphosate (720-2880 g/h a.i.) and ammonium glufosinate herbicides (375-1500 g/h a.i.) to control of common ragweed (Ambrosia artemisiifolia L.) has been studied in trials (2013-2018) in the vineyards of Rkatsiteli, Liang and Cabernet Sauvignon in Abinsk district of Krasnodar region. Accounting of weeds was done by a quantitative method with counting the number of each weed species in each plot. Counts were performed before the treatment and in 15, 30 and 45 days after spraying. The effi cacy of herbicide was determined in relation to the untreated control and expressed as a percentage. The main evaluation criterion was the eff ectiveness of 100 % in one of the accounts or the average (for all counts) effi ciency of more than 90 %. The results showed that in 95 % of trials spraying of 1440 g/h of glyphosate 1440 g/h of glyphosate (a.i.) and higher ensured processing effi ciency exceeding 90 %. Herbicides such as Roundup, containing 360 g/l of isopropylamine salt, can be recommended for use to control of common ragweed in the application rate 4.0 l/ha. Destruction of all common ragweed observed when using not less than 600 g/h glufosinate ammonium. Thus, Herbicides such as Basta, containing 150 g/l of ammonium glufosinate, to control of common ragweed should be applied by fractional application vegetative weeds (2.5 l/h + 1.5 l/h).

scholarly journals Research on the Computer Software Testing Method Based on Multiple Platforms

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Yongfang Sun ◽  
Jianjun Li
Keyword(s):  
Software Development ◽  
Software Testing ◽  
Computer Software ◽  
Test Accuracy ◽  
Testing Methods ◽  
Modern Life ◽  
Testing Method ◽  
Software Companies ◽  
And Control

Informationization plays an important role in modern life and production. And various software is one of the bases for it. Before it goes into service, software needs to go through many steps, including software development, design, etc. In software development, test is the key to identify and control bugs and errors in the software. Therefore, software companies often test the software to ensure that it is qualified. In recent years, more attention has been paid to a multi-platform computer software testing method, which can make up for defects in traditional testing methods to improve test accuracy. Firstly, this paper illustrates the connotation and features of software testing. Secondly, common software testing platforms and their requirements are analyzed. Finally, this paper proposes software testing method based on multiple platforms.

scholarly journals First Report of a Septoria sp. on Common Ragweed (Ambrosia artemisiifolia) in Europe

Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 696-696 ◽  
Author(s):  
Gy. Bohár ◽  
I. Schwarczinger
Keyword(s):  
Ambrosia Artemisiifolia ◽  
Voucher Specimen ◽  
Common Ragweed ◽  
History Museum ◽  
First Report ◽  
Leaf Spots ◽  
Brown Leaf ◽  
Detached Leaves ◽  
Pure Cultures ◽  
Hungarian Natural History Museum

During a survey for potential biocontrol agents of common ragweed (Ambrosia artemisiifolia var. elatior (L.) Descourt) in 1997, plants exhibiting irregular, brown leaf spots were collected repeatedly from six roadside locations in Pest County, Hungary. Many pycnidia developed in the necrotic tissues on detached leaves after 2 days in moist chambers. Pycnidia were globose to slightly flattened, brown, thin walled, 58 to 100 μm in diameter, with a definite ostiole. Conidia were hyaline, filiform with 2 to 3 septa, and 22.0 to 38.0 × 0.7 to 1.3 μm in size. The fungus was isolated on potato dextrose agar and identified as a Septoria sp. To confirm pathogenicity, potted ragweed seedlings were sprayed with a suspension of 5 × 106 conidia per ml from pure cultures of the Septoria sp., placed in a dew chamber for 72 h, and then grown in a greenhouse at 16 to 24°C. After 2 weeks, inoculated plants developed small, brown lesions on leaves and leaf petioles. Three weeks after inoculation, necrotic lesions had enlarged to 1 to 3 mm in diameter with irregular, distinct margins and light brown centers. The lesions on the lower leaves were larger and more numerous than on leaves nearer the tops of the plants. Pycnidia developed on the senescent leaves after 1 month. Infected leaves became completely necrotic and occasionally entire plants died. The pathogen was reisolated from all inoculated plants, thus satisfying Koch's postulates. A voucher specimen was deposited at the Department of Botany of the Hungarian Natural History Museum in Buda-pest (No. BP 92081). Septoria ambrosiae Hemmi et Naito was described on ragweed in Japan (1), but our isolate is morphologically distinct from that species. This is the first report of a Septoria sp. on A. artemisiifolia in Europe. Reference: (1) N. Naito. Mem. Coll. Agric. Kyoto 47:41, 1940.

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