scholarly journals Improved Efficacy of Newly Formulated Bacteriophages for Management of Bacterial Spot on Tomato

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 949-954 ◽  
Author(s):  
B. Balogh ◽  
J. B. Jones ◽  
M. T. Momol ◽  
S. M. Olson ◽  
A. Obradovic ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Residual Activity ◽  
Skim Milk ◽  
Field Trials ◽  
Plant Surface ◽  
Bacterial Spot ◽  
Corn Flour ◽  
Disease Reduction ◽  
Plant Foliage ◽  
Bacterial Spot Disease

Bacteriophages are currently used as an alternative method for controlling bacterial spot disease on tomato incited by Xanthomonas campestris pv. vesicatoria. However, the efficacy of phage is greatly reduced due to its short residual activity on plant foliage. Three formulations that significantly increased phage longevity on the plant surface were tested in field and greenhouse trials: (i) PCF, 0.5% pregelatinized corn flour (PCF) + 0.5% sucrose; (ii) Casecrete, 0.5% Casecrete NH-400 + 0.5% sucrose + 0.25% PCF; and (iii) skim milk, 0.75% powdered skim milk + 0.5% sucrose. In greenhouse experiments, the nonformulated, PCF-, Casecrete-, and skim milk-formulated phage mixtures reduced disease severity on plants compared with the control by 1, 30, 51, and 62%, respectively. In three consecutive field trials, nonformulated phage caused 15, 20, and 9% reduction in disease on treated plants compared with untreated control plants, whereas plants treated with PCF- and Casecrete-formulated phage had 27, 32, and 12% and 30, 43, and 24% disease reduction, respectively. Plants receiving copper-mancozeb treatments were included in two field trials and had a 20% decrease in disease in the first trial and a 13% increase in the second one. Skim milk-formulated phage was tested only once and caused an 18% disease reduction. PCF-formulated phage was more effective when applied in the evening than in the morning, reducing disease on plants by 27 and 13%, respectively. The Casecrete-formulated phage populations were over 1,000-fold higher than the nonformulated phage populations 36 h after phage application.

scholarly journals Control of Citrus Canker and Citrus Bacterial Spot with Bacteriophages

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1048-1052 ◽  
Author(s):  
Botond Balogh ◽  
B. I. Canteros ◽  
R. E. Stall ◽  
J. B. Jones
Keyword(s):  
Disease Severity ◽  
Residual Activity ◽  
Skim Milk ◽  
Citrus Canker ◽  
Bacterial Spot ◽  
Xanthomonas Axonopodis ◽  
Significant Control ◽  
Disease Reduction ◽  
Significant Disease ◽  
Phage Treatment

Bacteriophages, alone or in combination with copper bactericides, were evaluated for managing Asiatic citrus canker and citrus bacterial spot incited by Xanthomonas axonopodis pathovars citri and citrumelo, respectively. In a set of five greenhouse experiments, phage treatment provided consistent control of citrus canker, causing an average of 59% reduction in disease severity. However, treatment with phage was ineffective if applied with skim milk, a protective formulation, which increases phage residual activity. In nursery settings, phage treatment also reduced disease but was less effective than copper-mancozeb, a chemical bactericide. The integration of phage and copper-mancozeb resulted in equal or less control than copper-mancozeb application alone. Phage treatments were evaluated in a commercial citrus nursery for reducing citrus bacterial spot caused by natural inoculum. Phage treatment provided significant disease reduction on moderately sensitive Valencia oranges in two trials (48 and 35%); however, on the highly susceptible grapefruit host it was ineffective. In an experimental citrus nursery, phage treatment provided significant control of citrus bacterial spot caused by a phage-sensitive strain, but was equally or less effective than copper-mancozeb. The combination of phage and copper-mancozeb did not increase control compared with copper-mancozeb alone.

Effect of acidic electrolyzed water on the viability of bacterial and fungal plant pathogens and on bacterial spot disease of tomato

2006 ◽  
Vol 52 (10) ◽  
pp. 915-923 ◽  
Author(s):  
P A Abbasi ◽  
G Lazarovits
Keyword(s):  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Disease Incidence ◽  
Bacterial Spot ◽  
Tomato Seed ◽  
Electrolyzed Water ◽  
Spot Disease ◽  
Foliar Sprays ◽  
Fungal Plant Pathogens ◽  
Bacterial Spot Disease

Acidic electrolyzed water (AEW), known to have germicidal activity, was obtained after electrolysis of 0.045% aqueous solution of sodium chloride. Freshly prepared AEW (pH 2.3–2.6, oxidation–reduction potential 1007–1025 mV, and free active chlorine concentration 27–35 ppm) was tested in vitro and (or) on tomato foliage and seed surfaces for its effects on the viability of plant pathogen propagules that could be potential seed contaminants. Foliar sprays of AEW were tested against bacterial spot disease of tomato under greenhouse and field conditions. The viability of propagules of Xanthomonas campestris pv. vesicatoria (bacterial spot pathogen), Streptomyces scabies (potato scab pathogen), and Fusarium oxysporum f.sp. lycopersici (root rot pathogen) was significantly reduced 4–8 log units within 2 min of exposure to AEW. Immersion of tomato seed from infected fruit in AEW for 1 and 3 min significantly reduced the populations of X. campestris pv. vesicatoria from the surface of the seed without affecting seed germination. Foliar sprays of AEW reduced X. campestris pv. vesicatoria populations and leaf spot severity on tomato foliage in the greenhouse. In the field, multiple sprays of AEW consistently reduced bacterial spot severity on tomato foliage. Disease incidence and severity was also reduced on fruit, but only in 2003. Fruit yield was either enhanced or not affected by the AEW sprays. These results indicate a potential use of AEW as a seed surface disinfectant or contact bactericide.Key words: electrolyzed oxidizing water, seed disinfectant, foliar sprays, bacterial spot control.

scholarly journals A Monocot Plant Identified as an Alternate Host of the Causal Agent of Bacterial Spot of Tomato and Pepper

HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 969-972 ◽  
Author(s):  
Harold A.A. Gibbs
Keyword(s):  
Xanthomonas Campestris ◽  
In Planta ◽  
Bacterial Spot ◽  
Alternate Host ◽  
Spot Disease ◽  
Commelina Benghalensis ◽  
Weed Growth ◽  
Bacterial Spot Disease ◽  
Stem Extract ◽  
Physiological Reactions

Xanthomonas campestris pv. vesicatoria (Xcv) recovered from Commelina benghalensis L., caused bacterial spot disease in cultivars of pepper and tomato susceptible to the pathogen. This is the first reported case of a dicot-infecting Xc pathovar infecting a monocot plant, represented here by a member of the Family Commelinaceae. Laboratory strains of the pathogen that included 81-23, 81-23M13, 82:4, 2595, and P6AD4, known to be pathogenic to pepper and tomato, promoted bacterial spot symptoms on leaves of C. benghalensis L. Of the 63 field isolates recovered from infected C. benghalensis L., 30 gave biochemical and physiological reactions consistent with Xcv pathogens, whereas 10 of the latter promoted bacterial spot disease in the test cultivars resulting in the identification of seven pathogenic races, including P2, P5, P6, P5T1, P5T2, P6T2, and P6T3. Bacterial spot disease symptoms developed on stems only when C. benghalensis L. was spray-inoculated with strains 81-23, 81-23M13, and P6AD4. Bacterial concentration increased in planta by as much as 103 per lesion of the leaf, whereas growth of the same strains was restricted in the stem of this weed. Growth of these three strains was, however, significantly (P ≤ 0.05) lower on NYGA amended with C. benghalensis L. stem extract than on NYGA amended with leaf extract. The ability of the bacterial spot pathogen to infect the stem of C. benghalensis L. has serious implications for management of bacterial spot disease in fields populated with this weed since stems of this plant infected with the pathogen continue to grow vegetatively and disperse throughout all fields in which it is found.

scholarly journals Automatic Detection and Severity Assessment of Pepper Bacterial Spot Disease via MultiModels Based on Convolutional Neural Networks

2020 ◽  
Vol 11 (2) ◽  
pp. 29-43
Author(s):  
Qiufeng Wu ◽  
Miaomiao Ji ◽  
Zhao Deng
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Xanthomonas Campestris ◽  
Automatic Detection ◽  
Bacterial Disease ◽  
Severity Assessment ◽  
Bacterial Spot ◽  
Deep Convolutional Neural Networks ◽  
Spot Disease ◽  
Bacterial Spot Disease

Pepper bacterial spot disease caused by Xanthomonas campestris is the most common pepper bacterial disease, which ultimately reduces productivity and quality of products. This work uses deep convolutional neural networks (CNNs) to serve fine-grained pepper bacterial spot disease severity classification tasks. The pepper bacterial spot disease leaf images collected from the PlantVillage dataset are further annotated by botanists and split into healthy samples (label1), general samples (label2), and serious samples (label3). To extract more effective and discriminative features, an integrated neural network denoted as MultiModel_VGR is proposed for automatic detection and severity assessment of pepper bacterial spot disease, which is based on three powerful and popular deep learning architectures, namely VGGNet, GoogLeNet and ResNet. Compared with state-of-the-art single CNN architectures and binary-integrated MultiModels, MultiModel_VGR yields the best overall accuracy of 95.34% on the hold-out test dataset, which may have great potential in crop disease control for modern agriculture.

scholarly journals Genetic Mapping and Functional Analysis of the Tomato Bs4 Locus Governing Recognition of the Xanthomonas campestris pv. vesicatoria AvrBs4 Protein

2001 ◽  
Vol 14 (5) ◽  
pp. 629-638 ◽  
Author(s):  
Agim Ballvora ◽  
Michéle Pierre ◽  
Guido van den Ackerveken ◽  
Sebastian Schornack ◽  
Ombeline Rossier ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Resistance Locus ◽  
Bacterial Spot ◽  
Dna Templates ◽  
Nuclear Localization Signals ◽  
Bulked Dna ◽  
Capsicum Spp ◽  
Bacterial Spot Disease ◽  
Bacterial Spot Resistance ◽  
Susceptible Tomato

Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper (Capsicum spp.) and tomato (Lycopersicon spp.). Analysis of 17 different Lycopersicon accessions with avrBs4-expressing X. campestris pv. vesicatoria strains identified 15 resistant and two susceptible tomato genotypes. Genetic analysis revealed that AvrBs4 recognition in tomato is governed by a single locus, designated Bs4 (bacterial spot resistance locus no. 4). Amplified fragment length polymorphism and bulked DNA templates from resistant and susceptible plants were used to define a 2.6-cM interval containing the Bs4 locus. A standard tomato mapping population was employed to localize Bs4- linked markers on the short arm of chromosome 5. Investigation of X. campestris pv. vesicatoria hrp mutant strains revealed that AvrBs4 secretion and avirulence activity are hrp dependent. Agrobacterium-based delivery of the avrBs4 gene into tomato triggered a plant response that phenotypically resembled the hypersensitive response induced by avrBs4-expressing X. campestris pv. vesicatoria strains, suggesting symplastic perception of the avirulence protein. Mutations in the avrBs4 C-terminal nuclear localization signals (NLSs) showed that NLSs are dispensable for Bs4-mediated recognition. Our data suggest that tomato Bs4 and pepper Bs3 employ different recognition modes for detection of the highly homologous X. campestris pv. vesicatoria avirulence proteins AvrBs4 and AvrBs3.

scholarly journals Yield of Bell Peppers as Impacted by the Combination of Bacterial Spot and a Single Hail Storm: Will Copper Sprays Help?

1994 ◽  
Vol 4 (4) ◽  
pp. 356-358 ◽  
Author(s):  
C.S. Kousik ◽  
D.C. Sanders ◽  
D.F. Ritchie
Keyword(s):  
Xanthomonas Campestris ◽  
King Arthur ◽  
Bacterial Spot ◽  
Hail Damage ◽  
Previous Season ◽  
Fold Reduction ◽  
Bell Peppers ◽  
Bacterial Spot Disease ◽  
The Impact ◽  
Pepper Plants

The impact of a single hail storm injury in combination with bacterial spot caused by Xanthomonas campestris pv. vesicatoria was assessed on three commercial pepper (Capsicum annuum) cultivars—King Arthur, Jupiter, and Rebell. In addition, the effectiveness of copper plus maneb sprays on hail-damaged plants to suppress bacterial spot was evaluated. A hail storm of ≈5-min duration severely damaged and defoliated the pepper plants. Severe bacterial spot was observed 10 days later on all plants. Disease ratings taken 2 weeks after the hail storm were significantly greater than ratings before the storm. Unsprayed plots of all three cultivars had the greatest disease and the least yield. Plots sprayed weekly (7-day schedule) had a significantly greater yield and less disease compared to unsprayed and biweekly sprayed (14-day schedule) plots for all three cultivars. The combination of hail damage and bacterial spot resulted in a 6-fold reduction in yield in the absence of copper plus maneb sprays and a 2-fold reduction with weekly sprays when compared to the previous season with no hail injury, but similar levels of bacterial spot disease. Disease ratings were less and yields were greater for `King Arthur', than for `Jupiter' and `Rebell'. A judicious copper plus maneb spray program can suppress bacterial spot and help recovery of a young pepper crop when hail damage occurs.

Erratum to “Reclassification of the Xanthomonads Associated with Bacterial Spot Disease of Tomato and Pepper”

2006 ◽  
Vol 29 (1) ◽  
pp. 85-86 ◽  
Author(s):  
Jeffrey B. Jones ◽  
George H. Lacy ◽  
Hacene Bouzar ◽  
Robert E. Stall ◽  
Norman W. Schaad
Keyword(s):  
Bacterial Spot ◽  
Spot Disease ◽  
Bacterial Spot Disease

Comparative toxicity of foliar and systemic applications of acetamiprid and imidacloprid against the cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

1998 ◽  
Vol 88 (4) ◽  
pp. 437-442 ◽  
Author(s):  
A.R. Horowitz ◽  
Z. Mendelson ◽  
P.G. Weintraub ◽  
I. Ishaaya
Keyword(s):  
Bemisia Tabaci ◽  
Residual Activity ◽  
Field Trials ◽  
Adult Mortality ◽  
Cotton Field ◽  
Ovicidal Activity ◽  
Laboratory Conditions ◽  
Controlled Conditions ◽  
Comparative Toxicity ◽  
Cotton Whitefly

AbstractComparative bioassays of two chloronicotinyl insecticides, acetamiprid and imidacloprid, against the whitefly Bemisia tabaci (Gennadius), using foliar and systemic applications, were conducted under laboratory conditions and in field trials. Under controlled conditions, the ovicidal activity of foliar applications of acetamiprid on cotton seedlings was much higher than that of imidacloprid. According to LC50 and LC90 values, acetamiprid was 10- and 18-fold more potent than imidacloprid. Both compounds were effective when applied to soil against whitefly adults; however, the potency of imidacloprid was somewhat higher than that of acetamiprid 2, 7 and 14 days after application; resulting (with the concentration of 25 ml a.i./l) in adult mortality of 90, 93, and 96% and 76, 84, and 76% respectively. In an experimental cotton field, the efficacy of foliar applications of 60 g a.i./ha acetamiprid and 210 g a.i./ha imidacloprid was compared. Field residual activity of acetamiprid to whitefly adults lasted for approximately ten days, compared with three days for imidacloprid.

scholarly journals Resistance of Xanthomonas campestris pv. vesicatoria isolates from Tanzania to copper and implications for bacterial spot management

2014 ◽  
Vol 8 (30) ◽  
pp. 2881-2885 ◽  
Author(s):  
C. Shenge Kenneth ◽  
B. Mabagala Robert ◽  
N. Mortensen Carmen ◽  
Wydra Kerstin
Keyword(s):  
Xanthomonas Campestris ◽  
Bacterial Spot
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