Controlling Weeds with Phytopathogenic Bacteria

1996 ◽  
Vol 10 (3) ◽  
pp. 621-624 ◽  
Author(s):  
David R. Johnson ◽  
Donald L. Wyse ◽  
Keith J. Jones
Keyword(s):  
Weed Control ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Severe Disease ◽  
Jerusalem Artichoke ◽  
Field Conditions ◽  
Biological Weed Control ◽  
Spray Application ◽  
Phytopathogenic Bacteria ◽  
Annual Bluegrass

Until recently, phytopathogenic bacteria have not been considered potential biological weed control candidates because they lack the ability to penetrate intact plants. This deficiency can be overcome by providing entry wounds or using surfactants. Spray application ofPseudomonas syringaepv.tagetis(5 × 108cells/ml) in aqueous buffer with a surfactant produced severe disease in Canada thistle, common ragweed, Jerusalem artichoke, sunflower, and certain other members of the Compositae under field conditions. Spray application of the bacterium without surfactant was ineffective on all reported hosts.Xanthomonas campestrispv.poannuacontrolled annual bluegrass in bermudagrass golf greens when applied by spray during mowing. The bacterium entered through mowing injuries, causing lethal, systemic wilt. Application of the bacterium to annual bluegrass in the absence of fresh mowing injuries failed to produce symptoms. Under field conditions, this previously unknown pathovar's host range was limited to a single subspecies of annual bluegrass, but inundative application to freshly mowed turf resulted in infection of diverse annual bluegrass biotypes. In field trials, six monthly applications resulted in greater than 70% control. The preceding examples are among the first attempts to use foliar phytopathogenic bacteria for biological weed control. Efficacy of these bacterial bioherbicides and of future biocontrol strategies employing bacteria is dependent on facilitated host penetration.

Influence of host and pathogen variables on the efficacy of Phoma herbarum, a potential biological control agent of Taraxacum officinale

2002 ◽  
Vol 80 (4) ◽  
pp. 425-429 ◽  
Author(s):  
Silke Neumann ◽  
Greg J Boland
Keyword(s):  
Weed Control ◽  
Biological Control Agent ◽  
Severe Disease ◽  
Taraxacum Officinale ◽  
Control Agent ◽  
Biological Weed Control ◽  
Optimal Conditions ◽  
Potato Dextrose Broth ◽  
Phoma Herbarum ◽  
Important Host

Phoma herbarum Westendorp has been identified as a potential biological weed control agent (BWCA) for Taraxacum officinale Weber in turf. However, host and pathogen variables that influence the efficacy of this BWCA need to be identified to provide more optimal conditions for production and efficacy. In controlled-environment studies, 4-week-old T. officinale plants were significantly more susceptible to P. herbarum than were plants that were 6 and 8 weeks old, nonflowering but mature, budding, or flowering. Mycelial suspensions incited significantly more severe disease than conidia, and 5-day-old mycelial shake cultures incited significantly higher disease than 3-, 7-, 9-, 11-, or 13-day-old cultures. A concentration of 10 to 20% of mycelial fragments in potato dextrose broth (v/v) incited higher disease severity than 0, 40, 60, or 100%. These experiments identified several important host and pathogen variables that influence the efficacy of P. herbarum on T. officinale and established more optimal conditions for production and efficacy of this BWCA.Key words: biological weed control, bioherbicide, mycoherbicide, Taraxacum officinale, dandelion, Phoma herbarum.

scholarly journals Development of an Engineered Bioluminescent Reporter Phage for Detection of Bacterial Blight of Crucifers

2012 ◽  
Vol 78 (10) ◽  
pp. 3592-3598 ◽  
Author(s):  
David A. Schofield ◽  
Carolee T. Bull ◽  
Isael Rubio ◽  
W. Patrick Wechter ◽  
Caroline Westwater ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Xanthomonas Campestris ◽  
Cultured Cells ◽  
Severe Disease ◽  
Disease Diagnosis ◽  
Diseased Plant ◽  
Content Type ◽  
Genes Encoding ◽  
Type Phage

ABSTRACTBacterial blight, caused by the phytopathogenPseudomonas cannabinapv.alisalensis, is an emerging disease afflicting important members of theBrassicaceaefamily. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogenPseudomonas syringaepv.maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant “light”-tagged reporter phage was generated by integrating bacterialluxABgenes encoding luciferase into the genome ofP. cannabinapv.alisalensisphage PBSPCA1. The PBSPCA1::luxABreporter phage is viable and stable and retains properties similar to those of the wild-type phage. PBSPCA1::luxABrapidly and sensitively detectsP. cannabinapv.alisalensisby conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens ofBrassicaspecies such asP. syringaepv.maculicola,Pseudomonas marginalis,Pectobacterium carotovorum,Xanthomonas campestrispv.campestris, andX. campestrispv.raphanieither do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detectsP. cannabinapv.alisalensison diseased plant specimens, indicating its potential for disease diagnosis.

scholarly journals Screening Tomato Seedlings for Resistance to Bacterial Spot

HortScience ◽  
1994 ◽  
Vol 29 (6) ◽  
pp. 680-682 ◽  
Author(s):  
G. Cameron Somodi ◽  
J.B. Jones ◽  
J.W. Scott ◽  
J.P. Jones
Keyword(s):  
Lycopersicon Esculentum ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Field Conditions ◽  
Screening Procedure ◽  
Screening Methods ◽  
Bacterial Spot ◽  
Inoculation Technique ◽  
Tomato Seedlings ◽  
Spray Inoculation

A `spray-inoculation seedling screening procedure was developed for detecting resistance to Xanthomonas campestris pv. vesicatoria (Doidge) Dye, causal agent of bacterial spot of tomato (Lycopersicon esculentum Mill.). Two-week-old transplants were preconditioned under 95% humidity for 16 hours before spray inoculation and then rated for bacterial spot 2 weeks later. Resistant plants could also be distinguished from susceptible genotypes using a modified bacterial speck [Pseudomonas syringae pv. tomato (Okabe) Young, Dye, and Wilkie] screening procedure (cotyledon-dip technique). When results of both screening methods were compared to field ratings from three previous seasons, significant correlations were more frequently observed for the spray-inoculation method. In Summer 1991, individual plants were evaluated by the spray-inoculation technique and then were placed in the field to determine susceptibility under field conditions. Correlations (r = 0.28 to 0.34) between spray-inoculation seedling screening ratings and field ratings, although low, were significant (P ≤ 0.0001). More than 90% of susceptible plants could be eliminated, saving labor, space, and time.

Antagonistic Activity of Azotobаcter vinelandii IMV B-7076 against Phytopathogenic Microorganisms

2020 ◽  
Vol 82 (5) ◽  
pp. 21-29
Author(s):  
N.V. Chuiko ◽  
◽  
A.Yu. Chobotarov ◽  
Ya.I. Savchuk ◽  
I.M. Kurchenko ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Antibacterial Properties ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Biologically Active ◽  
Fungal Mycelium ◽  
Phytopathogenic Bacteria ◽  
Bacterial Preparation

Bacteria of the genus Azotobacter are known for their ability to stimulate plant growth and development. Azotobacter vinelandii IMV B-7076 strain was isolated from Zhytomyr region soil of Ukraine. It is one of the components of the "Azogran" complex bacterial preparation for plant growing. It has been established that A. vinelandii IMV B-7076 synthesizes biologically active substances that promote plant development. At the same time, the antagonistic activity of A. vinelandii IMV B-7076 against phytopathogens has not yet been studied, so this became the aim of this work. Methods. The antagonistic activity of A. vinelandii IMV B-7076 was determined by agar well diffusion and agar blocks methods. Results. It was shown that A. vinelandii IMV B-7076 had antagonistic activity against some phytopathogenic fungi. In particular, the diameter of growth inhibition zones of Alternaria alternata 16861, Fusarium avenaceum 50720, Fusarium verticillioides 50463, Fusarium lactis 50719, Fusarium oxysporum 54201, Fusarium poae 50704 was 14-37 mm, Bipolaris sorokiniana 16868 and Fusarium solani – 11-13 mm. Fusarium culmorum 50716 and Fusarium graminearum 50662 were not sensitive to A. vinelandii IMV B-7076 metabolites. Notably, the antagonistic effect was demonstrated in mycelial growth and spore formation inhibition, in fungal mycelium discoloration. It was also demonstrated that A. vinelandii IMV B-7076 did not show antagonistic activity against phytopathogenic bacteria Agrobacterium tumefaciens 8628, Pectobacterium carotovorum subsp. carotovorum 8982, Pseudomonas fluorescens 8573, Pseudomonas syringae pv. syringae 8511, Clavibacter michiganensis subsp. michiganensis 13a, Xanthomonas campestris pv. campestris 8003b. Conclusions. Studied A. vinelandii IMV B-7076 strain is characterized by antagonistic activity against phytopathogenic fungi and does not have antibacterial properties against phytopathogenic bacteria. The antifungal activity of A. vinelandii IMV B-7076, as a component of "Azogran", will be useful for this bacterial preparation application in plant growing.

scholarly journals A preliminary study of antibacterial activity of thirty essential oils against several important plant pathogenic bacteria

2018 ◽  
Vol 33 (3-4) ◽  
pp. 185-195 ◽  
Author(s):  
Tatjana Popovic ◽  
Zoran Milicevic ◽  
Violeta Oro ◽  
Igor Kostic ◽  
Vesela Radovic ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Essential Oils ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Maximum Diameter ◽  
Silver Fir ◽  
Phytopathogenic Bacteria ◽  
Plant Pathogenic Bacteria

Numerous scientific research studies all over the world have addressed the problem of agriculture in the 21st century as being particularly sensitive to climate change, which has caused phytopathogenic bacteria to spread. Therefore, there is a clear and urgent need to contain this kind of risk in agricultural production (both conventional and organic farming). The objective of this study was to determine the antibacterial activity of 30 essential oils (EOs) against three harmful plant pathogenic bacteria of agricultural importance, Erwinia amylovora, Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. syringae. The study included in vitro testing, using an agar-diffusion assay. The EOs of Ceylon cinnamon (leaf and bark), oregano, clove bud and palmarosa revealed antibacterial activity against the test bacteria, and the maximum mean inhibition zone diameters of 35 mm was found against E. amylovora and X. campestris pv. campestris (highly sensitive reaction), while it was smaller in the case of P. syringae pv. syringae, from 18.25-26.25 mm (sensitive to very sensitive reaction). Maximum diameter of the zone of inhibition (35 mm) was obtained using basil and peppermint against E. amylovora, and rosemary, blue gum and camphor tree against X. campestris pv. campestris. Not a single EO inhibited P. syringae pv. syringae with the resulting total diameter zone of 35 mm, and this test bacteria was resultingly classified as the least susceptible bacterium of the three tested. EOs of lemongrass, aniseed, ylang ylang, silver fir, lemon, dwarf mountain pine, bay laurel and scots pine caused sensitive reaction of the tested bacteria. Peppermint, black cumin, Indian frankincense, bergamot orange, common juniper, bitter orange and neem produced variable reactions from total to weakly or no inhibition at all. Weakly activity was found in niaouli and Atlas cedar. Eastern red cedar, patchouli, Indian sandalwood and ginger caused no reaction of any of the test bacteria. The results offer a basis for further work based on in vivo testing for the purpose of developing ?natural pesticides? for control of phytopathogenic bacteria, thus giving a significant contribution to reducing yield losses in agriculture and sustainable development.

scholarly journals Bactericidal Activity of Larrea tridentata Hydroalcoholic Extract against Phytopathogenic Bacteria

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 957
Author(s):  
Ana Lizet Morales-Ubaldo ◽  
Nallely Rivero-Perez ◽  
Fidel Avila-Ramos ◽  
Eliazar Aquino-Torres ◽  
Judith Prieto-Méndez ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pseudomonas Syringae ◽  
Bactericidal Activity ◽  
Xanthomonas Campestris ◽  
Larrea Tridentata ◽  
Minimal Bactericidal Concentration ◽  
Organic Fraction ◽  
Clavibacter Michiganensis ◽  
Hydroalcoholic Extract ◽  
Phytopathogenic Bacteria

Due to the emergence of bacterial resistance in phytopathogenic microorganisms, it is necessary to search for new treatment alternatives for these pathogens. Natural extracts are a potential source of bioactive compounds that can act against such bacterial strains. The antibacterial activity of Larrea tridentata against bacteria with public health importance has been documented; however, few reports cover pathogens associated with the agricultural sector. The aim of the present study was to evaluate the antibacterial activity of Larrea tridentata hydroalcoholic extract (LTHE) and fractions against phytopathogenic bacteria. LTHE was obtained by the maceration technique and then subjected to bipartition using solvents of different polarities. Clavibacter michiganensis sbsp. michiganensis, Pseudomonas syringae, and Xanthomonas campestris strains were used, and their antibiotic sensitivity was determined. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of LTHE and its fractions (aqueous: LTAq-F; organic: LTEtOAc-F) were determined. LTHE and its organic fraction showed bactericidal activity against the three bacteria, showing better activity against X. campestris, exhibiting an MIC of 0.39 mg/mL and an MBC of 0.78 mg/mL. The results show that LTHE and its organic fraction have bactericidal activity in vitro against Clavibacter michiganensis sbsp. michiganensis, Pseudomonas syringae, and Xanthomonas campestris.

Comparative Mapping of Three Bacterial, Three Fungal, and One Virus Disease-resistance Genes in Common Bean

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 547a-547
Author(s):  
Geunhwa Jung ◽  
James Nienhuis ◽  
Dermot P. Coyne ◽  
H.M. Ariyarathne
Keyword(s):  
Disease Resistance ◽  
Common Bean ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Fungal Pathogens ◽  
Xanthomonas Campestris ◽  
Virus Disease ◽  
Disease Resistance Genes ◽  
Brown Spot ◽  
Viral Pathogen

Common bacterial blight (CBB), bacterial brown spot (BBS), and halo blight (HB), incited by the bacterial pathogens Xanthomonas campestris pv. phaseoli (Smith) Dye, Pseodomonas syringae pv. syringa, and Pseudomonas syringae pv. phaseolicola, respectively are important diseases of common bean. In addition three fungal pathogens, web blight (WB) Thanatephorus cucumeris, rust Uromyces appendiculatus, and white mold (WM) Sclerotinia sclerotiorum, are also destructive diseases attacking common bean. Bean common mosaic virus is also one of most major virus disease. Resistance genes (QTLs and major genes) to three bacterial (CBB, BBS, and HB), three fungal (WB, rust, and WM), and one viral pathogen (BCMV) were previously mapped in two common bean populations (BAC 6 × HT 7719 and Belneb RR-1 × A55). The objective of this research was to use an integrated RAPD map of the two populations to compare the positions and effect of resistance QTL in common bean. Results indicate that two chromosomal regions associated with QTL for CBB resistance mapped in both populations. The same chromosomal regions associated with QTL for disease resistance to different pathogens or same pathogens were detected in the integrated population.

scholarly journals In VitroActivity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

2014 ◽  
Vol 81 (1) ◽  
pp. 432-440 ◽  
Author(s):  
T. Sotelo ◽  
M. Lema ◽  
P. Soengas ◽  
M. E. Cartea ◽  
P. Velasco
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Degradation Products ◽  
Allyl Isothiocyanate ◽  
Leaf Extracts ◽  
Soil Pathogens ◽  
Content Type ◽  
Positive Effects

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.

scholarly journals Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

2021 ◽  
Author(s):  
Marco Grella ◽  
Fabrizio Gioelli ◽  
Paolo Marucco ◽  
Ingrid Zwertvaegher ◽  
Eric Mozzanini ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Plant Protection ◽  
Plant Protection Products ◽  
Field Conditions ◽  
Advanced Technology ◽  
Real Field ◽  
Spray Application ◽  
Spray System

AbstractThe pulse width modulation (PWM) spray system is the most advanced technology to obtain variable rate spray application without varying the operative sprayer parameters (e.g. spray pressure, nozzle size). According to the precision agriculture principles, PWM is the prime technology that allows to spray the required amount where needed without varying the droplet size spectra which benefits both the uniformity of spray quality and the spray drift reduction. However, some concerns related to the effect of on–off solenoid valves and the alternating on/off action of adjacent nozzles on final uneven spray coverage (SC) have arisen. Further evaluations of PWM systems used for spraying 3D crops under field conditions are welcomed. A tower-shaped airblast sprayer equipped with a PWM was tested in a vineyard. Twelve configurations, combining duty cycles (DC: 30, 50, 70, 100%) and forward speeds (FS: 4, 6, 8 km h−1), were tested. Two methodologies, namely field-standardized and real field conditions, were adopted to evaluate the effect of DC and FS on (1) SC variability (CV%) along both the sprayer travel direction and the vertical spray profile using long water sensitive papers (WSP), and (2) SC uniformity (IU, index value) within the canopy at different depths and heights, respectively. Furthermore, the SC (%) and deposit density (Nst, no stains cm−2), determined using short WSP, were used to evaluate the spray application performances taking into account the spray volumes applied. Under field-controlled conditions, the pulsing of the PWM system affects both the SC variability measured along the sprayer travel direction and along the vertical spray profile. In contrast, under real field conditions, the PWM system does not affect the uniformity of SC measured within the canopy. The relationship between SC and Nst allowed identification of the ranges of 200–250 and 300–370 l ha−1 as the most suitable spray volumes to be applied for insecticide and fungicide plant protection products, respectively.

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