scholarly journals Application of Acibenzolar-S-Methyl Enhances Host Resistance in Tomato Against Ralstonia solanacearum

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 989-993 ◽  
Author(s):  
P. M. Pradhanang ◽  
P. Ji ◽  
M. T. Momol ◽  
S. M. Olson ◽  
J. L. Mayfield ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Field Conditions ◽  
Resistant Cultivars ◽  
Moderately Resistant ◽  
Wilt Incidence

The chemical elicitor acibenzolar-S-methyl (ASM; Actigard 50 WG), which induces systemic acquired resistance (SAR), was investigated to determine the effect on bacterial wilt of tomato caused by Ralstonia solanacearum on moderately resistant cultivars under greenhouse and field conditions. In greenhouse experiments, ASM was applied as foliar spray and/or soil drench (3 μg/ml) before and as foliar spray (30 μg/ml) after transplanting. The chemical elicitor was ineffective in reducing bacterial wilt incidence on susceptible tomato cultivars Equinox and FL 47 when plants were inoculated with R. solanacearum. However, greenhouse studies indicated that ASM significantly enhanced resistance in cultivars with moderate resistance to bacterial wilt such as Neptune and BHN 466. It appeared that ASM-mediated resistance was partially due to prevention of internal spread of R. solanacearum toward upper stem tissues of tomato plants. The effect of ASM on moderately resistant cultivars was consistent in field experiments conducted in 2002 and 2003 in Quincy, FL, where bacterial wilt incidence was significantly reduced in ASM-treated BHN 466 (in 2002), FL 7514 (in 2003), and Neptune (both years) plants. ASM-treated BHN 466 and FL 7514 produced significantly higher tomato yield than the untreated controls. This is the first report of ASM-mediated control of bacterial wilt under field conditions, which suggests that use of this treatment for moderately resistant genotypes may be effective for control of bacterial wilt of tomato.

scholarly journals Foliar Applications of Acibenzolar-S-Methyl Negatively Affect the Yield of Grafted Tomatoes in Fields Infested with Ralstonia solanacearum

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 890-894 ◽  
Author(s):  
Sanju Kunwar ◽  
Mathews L. Paret ◽  
Joshua H. Freeman ◽  
Laura Ritchie ◽  
Stephen M. Olson ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Disease Incidence ◽  
Foliar Spray ◽  
Additional Treatment ◽  
Marketable Yield ◽  
The Impact ◽  
Wilt Incidence

Three field experiments were conducted in Florida from 2012-2014 to assess the impact of acibenzolar-S-methyl (ASM), a systemic acquired-resistance inducer, applied as foliar spray or through drip-irrigation lines, on bacterial wilt incidence and yield of grafted tomatoes. The experiments were conducted in a field with race 1, biovar 1 strain of Ralstonia solanacearum, causal agent of tomato bacterial wilt. In all three experiments, the susceptible tomato variety BHN 602, grafted onto a resistant rootstock BHN 998, was compared with nongrafted BHN 602, treated with or without foliar applications of ASM and with grafted plants treated with foliar applications of ASM. In two experiments, an additional treatment of drip applications of ASM on grafted and nongrafted plants was evaluated. Grafting alone or in combination with drip applications of ASM (178.6 μM) significantly reduced disease incidence and increased total marketable yield relative to nongrafted treatments. There were no significant differences between grafted plants with or without drip ASM applications in terms of bacterial wilt incidence or total marketable yield. However, we demonstrate for the first time that foliar ASM applications on grafted plants negatively affects the total marketable yield compared with drip ASM applications on grafted plants or nontreated grafted control.

scholarly journals Effect of Application Frequency and Reduced Rates of Acibenzolar-S-Methyl on the Field Efficacy of Induced Resistance Against Bacterial Spot on Tomato

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Cheng-Hua Huang ◽  
Gary E. Vallad ◽  
Shouan Zhang ◽  
Amin Wen ◽  
Botond Balogh ◽  
...  
Keyword(s):  
Disease Severity ◽  
Untreated Control ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Field Trials ◽  
Plant Diseases ◽  
Bacterial Spot ◽  
Field Efficacy

Acibenzolar-S-methyl (ASM), a plant activator known to induce systemic acquired resistance, has demonstrated an ability to manage a number of plant diseases, including bacterial spot on tomato caused by four distinct Xanthomonas spp. The aim of this study was to evaluate application rate and frequency of ASM in order to optimize field efficacy against bacterial spot in Florida, while minimizing its impact on marketable yields. ASM was applied biweekly (once every 2 weeks) as a foliar spray at a constant concentration of 12.9, 64.5, and 129 μM throughout four field experiments during 2007–08. A standard copper program and an untreated control were also included. Overall, biweekly applications of ASM did not significantly reduce disease development or the final disease severity of bacterial spot compared with the copper-mancozeb standard or the untreated control. Only one experiment showed a significant reduction in the final disease severity on plants treated with ASM at 129 μM compared with the untreated control. Three additional field trials conducted during 2009–10 to evaluate the effects of weekly and biweekly applications of ASM at concentrations of 30.3 to 200 μM found that weekly applications provided significantly better disease control than biweekly applications. The tomato yields were not statistically improved with the use of ASM relative to the untreated control and standard copper program. Weekly ASM applications at rates as low as 75 μM (equivalent to 1.58 g a.i./ha in 100 liters of water or 0.21 oz. a.i./acre in 100 gallons of water) to 200 μM (equivalent to 4.20 g a.i./ha in 100 liters of water or 0.56 oz. a.i./acre in 100 gallons of water) were statistically equivalent in managing bacterial spot of tomato without significantly reducing yield compared with the untreated control.

scholarly journals Effects of Integrating Cultivar Resistance and Fungicide Application on Fusarium Head Blight and Deoxynivalenol in Winter Wheat

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 554-560 ◽  
Author(s):  
Stephen N. Wegulo ◽  
William W. Bockus ◽  
John Hernandez Nopsa ◽  
Erick D. De Wolf ◽  
Kent M. Eskridge ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Economic Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Resistant Cultivars ◽  
Fungicide Application ◽  
Fungicide Efficacy ◽  
Moderately Resistant

Fusarium head blight (FHB) or scab, incited by Fusarium graminearum, can cause significant economic losses in small grain production. Five field experiments were conducted from 2007 to 2009 to determine the effects on FHB and the associated mycotoxin deoxynivalenol (DON) of integrating winter wheat cultivar resistance and fungicide application. Other variables measured were yield and the percentage of Fusarium-damaged kernels (FDK). The fungicides prothioconazole + tebuconazole (formulated as Prosaro 421 SC) were applied at the rate of 0.475 liters/ha, or not applied, to three cultivars (experiments 1 to 3) or six cultivars (experiments 4 and 5) differing in their levels of resistance to FHB and DON accumulation. The effect of cultivar on FHB index was highly significant (P < 0.0001) in all five experiments. Under the highest FHB intensity and no fungicide application, the moderately resistant cultivars Harry, Heyne, Roane, and Truman had less severe FHB than the susceptible cultivars 2137, Jagalene, Overley, and Tomahawk (indices of 30 to 46% and 78 to 99%, respectively). Percent fungicide efficacy in reducing index and DON was greater in moderately resistant than in susceptible cultivars. Yield was negatively correlated with index, with FDK, and with DON, whereas index was positively correlated with FDK and with DON, and FDK and DON were positively correlated. Correlation between index and DON, index and FDK, and FDK and DON was stronger in susceptible than in moderately resistant cultivars, whereas the negative correlation between yield and FDK and yield and DON was stronger in moderately resistant than in susceptible cultivars. Overall, the strongest correlation was between index and DON (0.74 ≤ R ≤ 0.88, P ≤ 0.05). The results from this study indicate that fungicide efficacy in reducing FHB and DON was greater in moderately resistant cultivars than in susceptible ones. This shows that integrating cultivar resistance with fungicide application can be an effective strategy for management of FHB and DON in winter wheat.

scholarly journals Screening Cultivated Eggplant and Wild Relatives for Resistance to Bacterial Wilt (Ralstonia solanacearum)

Agriculture ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 157 ◽  
Author(s):  
Namisy ◽  
Chen ◽  
Prohens ◽  
Metwally ◽  
Elmahrouk ◽  
...  
Keyword(s):  
High Temperatures ◽  
Resistance Genes ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Solanum Melongena ◽  
Wild Relatives ◽  
Sources Of Resistance ◽  
Race 1 ◽  
Moderately Resistant ◽  
Phylotype I

Bacterial wilt, caused by Ralstonia solanacearum, is highly diverse and the identification of new sources of resistance for the incorporation of multiple and complementary resistance genes in the same cultivar is the best strategy for durable and stable resistance. The objective of this study was to screen seven accessions of cultivated eggplant (Solanum melongena L.) and 40 accessions from 12 wild relatives for resistance to two virulent R. solanacearum strains (Pss97 and Pss2016; phylotype I, race 1, biovar 3). The resistant or moderately resistant accessions were further evaluated with Pss97 in a second trial under high temperatures (and also with Pss2016 for S. anguivi accession VI050346). The resistant control EG203 was resistant to Pss97, but only moderately resistant to Pss2016. One accession of S. sisymbriifolium (SIS1) and two accessions of S. torvum (TOR2 and TOR3) were resistant or moderately resistant to Pss97 in both trials. Solanum anguivi VI050346, S. incanum accession MM577, and S. sisymbriifolium (SIS1 and SIS2) were resistant to Pss2016 in the first trial. However, S. anguivi VI050346 was susceptible in the second trial. These results are important for breeding resistant rootstocks and cultivars that can be used to manage this endemic disease.

scholarly journals Field Control of Bacterial Spot and Bacterial Speck of Tomato Using a Plant Activator

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 481-488 ◽  
Author(s):  
F. J. Louws ◽  
M. Wilson ◽  
H. L. Campbell ◽  
D. A. Cuppels ◽  
J. B. Jones ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Production Systems ◽  
Acquired Resistance ◽  
Dry Weight ◽  
Bacterial Spot ◽  
Population Densities ◽  
Bacterial Speck ◽  
Plant Activator

Acibenzolar-S-methyl (CGA 245704 or Actigard 50WG) is a plant activator that induces systemic acquired resistance (SAR) in many different crops to a number of pathogens. Acibenzolar-S-methyl was evaluated for management of bacterial spot (Xanthomonas axonopodis pv. vesicatoria) and bacterial speck (Pseudomonas syringae pv. tomato) of tomato in 15 and 7 field experiments, respectively. Experiments were conducted over a 4-year period in Florida, Alabama, North Carolina, Ohio, and Ontario using local production systems. Applied at 35 g a.i. ha-1, acibenzolar-S-methyl reduced foliar disease severity in 14 of the 15 bacterial spot and all 7 bacterial speck experiments. Disease control was similar or superior to that obtained using a standard copper bactericide program. Acibenzolar-S-methyl also reduced bacterial fruit spot and speck incidence. Tomato yield was not affected by using the plant activator in the field when complemented with fungicides to manage foliar fungal diseases, but tomato transplant dry weight was negatively impacted. X. axonopodis pv. vesicatoria population densities on greenhouse-grown tomato transplants were reduced by acibenzolar-S-methyl treatment. Bacterial speck and spot population densities on leaves of field-grown plants were not dramatically affected. Acibenzolar-S-methyl can be integrated as a viable alternative to copper-based bactericides for field management of bacterial spot and speck, particularly where copper-resistant populations predominate.

Host suitability of different wheat lines to Pratylenchus thornei under naturally infested field conditions in Turkey

Nematology ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 557-571 ◽  
Author(s):  
Abdelfattah A. Dababat ◽  
Fouad Mokrini ◽  
Salah-Eddine Laasli ◽  
Şenol Yildiz ◽  
Gül Erginbas-Orakci ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Conditions ◽  
Nematode Reproduction ◽  
Pratylenchus Thornei ◽  
Wide Range ◽  
Infested Field ◽  
Breeding Programmes ◽  
Moderate Resistance ◽  
Wheat Lines ◽  
Moderately Resistant

Summary The root-lesion nematode, Pratylenchus thornei, attacks a wide range of crops and causes significant reductions in global grain production. Breeding programmes are currently restricted to using parents with moderate resistance to P. thornei as cereal cultivars with complete resistance are yet to be identified. This study evaluated 484 of CIMMYT’s spring wheat accessions for resistance to P. thornei of which 56 lines were pre-identified as resistant under controlled growth room conditions. These lines were further evaluated for their resistance and tolerance reactions under field conditions, where 14 accessions maintained their resistance and 16 were moderately resistant against P. thornei. Four lines gave excellent resistant and tolerance reactions to P. thornei. The relationship between the nematode reproduction factor (Pf/Pi) and wheat grain yield in field experiments fits a linear regression model. These findings could be useful for improving P. thornei resistance in wheat.

scholarly journals Biovar Differentiation and Variation in Virulence of Ralstonia solanacearum Isolates Infecting Solanaceous Vegetables

2016 ◽  
Vol 2 ◽  
pp. 22-26 ◽  
Author(s):  
Ram Devi Timila ◽  
Shrinkhala Manandhar
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Negative Impact ◽  
Virulent Strain ◽  
Solanum Melongena ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Slight Variation ◽  
Solanaceae Family ◽  
Moderately Resistant

Bacterial wilt caused by Ralstonia solanacearum E.F. Smith is one of the destructive diseases of solanaceous vegetables specially tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). Experiments were conducted to determine biovar types existing among the strains or isolates of Nepal and variation in virulence in some vegetables belonging to solanaceae family. A total of 39 isolates infecting tomato, eggplant, chilli and potato collected from different parts of Nepal were analyzed for biovar types on the basis of 3 disaccharides and 3 hexose alcohols oxidation test.  Experiments were conducted to determine variation in virulence or aggressiveness of some of the  isolates under  screen house conditions using three host differentials such as Pusa Ruby (susceptible), Bishesh (moderately resistant) and Srijana (resistant) tomato cultivars. Of the 39 isolates, 23 were biovar III, three biovar II, three biovar IV, and one was biovar I. Nine isolates could not be differentiated into any of the five biovars. For breeding and epidemiological purposes it is very important to analyze the variability of aggressiveness. A total of 5 isolates collected from different places were included in the test. Isolates from Bhaktapur was found the most virulent causing wilt in the variety Bishesh (moderately resistant). Other isolates had the negative impact with zero wilt on the differentials used. Isolates from Jungekhola of Dhading district did not induce wilt even on susceptible variety (Pusa Ruby), but exhibited only senescence reaction. The result indicated that there is some slight variation among the isolates tested. Some effective management tactics might be needed in those locations where highly aggressive or virulent strain of bacterial wilt is prevalent, because resistant variety may not be stable in such locations.

scholarly journals Comparison of Methods of Acibenzolar-S-Methyl Application for Post-Infection Fire Blight Suppression in Pear and Apple

Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1125-1131 ◽  
Author(s):  
Kenneth B. Johnson ◽  
Todd N. Temple
Keyword(s):  
Fire Blight ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Field Research ◽  
Apple Rootstocks ◽  
Pr Genes ◽  
Treatment Timing ◽  
Guide Field ◽  
Pathogenesis Related

Greenhouse-grown, 1-year-old potted ‘Bosc’ pear and apple rootstock cultivars ‘M.9’ and ‘M.26’ were inoculated with the fire blight pathogen, Erwinia amylovora, and subjected to trunk paint, root drench, or foliar spray treatments with acibenzolar-S-methyl (ASM, 4 to 30 mg a.i./tree) to induce systemic acquired resistance. Each method of ASM treatment suppressed fire blight canker expansion by 22 to 25%. Furthermore, ASM application method and ASM treatment timing (at or ±3 weeks relative to inoculation) interacted significantly (P ≤ 0.02) in each experiment. A root drench was most effective when applied 3 weeks before inoculation (36% suppression) whereas trunk paints and foliar sprays were more effective at inoculation (43 and 34%, suppression, respectively). Sizes of fire blight cankers in potted apple rootstocks M.9 and M.26 (under scions ‘Gala’ or ‘Cameo’) inoculated directly with the pathogen were reduced by 82 and 87% after two pretreatments of ASM applied as a trunk paint or root drench, respectively. Expression of pathogenesis-related (PR) genes PR-1 and -2 in apple leaves sampled after an ASM trunk paint were elevated significantly (P ≤ 0.05) relative to control trees for at least 9 weeks after treatment. Results of this study are being used to guide field research on postinfection therapy with ASM in 1- to 10-year-old pear and apple trees where fire blight has proven difficult to manage with therapeutic pruning only.

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