scholarly journals Evidence that Prohexadione-Calcium Induces Structural Resistance to Fire Blight Infection

2009 ◽  
Vol 99 (5) ◽  
pp. 591-596 ◽  
Author(s):  
Molly J. McGrath ◽  
Jessica M. Koczan ◽  
Megan M. Kennelly ◽  
George W. Sundin
Keyword(s):  
Cell Wall ◽  
Disease Control ◽  
Disease Severity ◽  
Growth Regulator ◽  
Fire Blight ◽  
Shoot Growth ◽  
Disease Incidence ◽  
Wall Width ◽  
Structural Resistance ◽  
Prohexadione Calcium

Mechanisms of fire blight control by the shoot-growth regulator prohexadione-calcium (ProCa) were investigated by comparing disease development in ProCa-treated potted apple trees (cv. Gala) to paclobutrazol (another shoot-growth regulator)-treated and nontreated trees and in ProCa-treated cv. McIntosh trees in the field. Twenty-eight days after inoculation with Erwinia amylovora Ea110, disease incidence on ProCa- and paclobutrazol-treated shoots was significantly reduced compared with that on nontreated shoots. Disease severity (percent shoot length infected) was also significantly lower on both ProCa- and paclobutrazol-treated shoots than on nontreated shoots. However, bacterial populations within inoculated shoots were high and bacterial growth occurred in all treatments. In addition, the mean cell wall width of the cortical parenchyma midvein tissue of the first and second youngest unfolded leaves of ProCa- and paclobutrazol-treated shoots was significantly wider both 0.5 and 2 cm from the leaf tips compared with the cell walls of the nontreated tissue. Taken together, these results suggest that reduction of fire blight symptoms by ProCa and paclobutrazol is not the result of reduced populations of E. amylovora in shoots. Moreover, because paclobutrazol also reduced disease severity and incidence, changes in flavonoid metabolism induced by ProCa but not paclobutrazol does not appear to be responsible for disease control as suggested in recent literature. Finally, although this study did not directly link disease control to the observed cell wall changes, the possibility that an increase in cell wall width impedes the spread of E. amylovora should be investigated in more depth.

scholarly journals Multiple Treatment Meta-Analysis of Products Evaluated for Control of Fire Blight in the Eastern United States

2011 ◽  
Vol 101 (5) ◽  
pp. 512-522 ◽  
Author(s):  
H. K. Ngugi ◽  
B. L. Lehman ◽  
L. V. Madden
Keyword(s):  
United States ◽  
Biological Control ◽  
Disease Control ◽  
Plant Defense ◽  
Fire Blight ◽  
Pantoea Agglomerans ◽  
Effect Sizes ◽  
Eastern United States ◽  
The Mean ◽  
Prohexadione Calcium

The aim of this analysis was to estimate the effect sizes and consistency of products evaluated for fire blight control in the eastern United States over the last decade. Because only 3% of the 69 studies published from 2000 to 2008 explicitly presented a measure of within-study variability, a method for estimating the least significant difference (LSD) and, hence the sampling variance, for studies with at least two significant mean separations in the presented mean multiple comparisons was developed. Lin's concordance analysis indicated that the estimated LSD was an accurate predictor of the actual LSD based on 35 studies in a calibration evaluation (ρc = 0.997). Separate multi-treatment random-effects meta-analyses were performed for three control categories: antibiotics, biological control, and plant defense-activating products and mean log response ratios relative to the nontreated controls ([Formula: see text]) were computed for each treatment and then back-transformed to obtain the mean percent disease control. None of the products evaluated performed as well as streptomycin, the standard product for fire blight control, for which the mean disease control was 68.6%. As a group, experimental antibiotics provided the best fire blight control with mean effect sizes ranging from 59.7 to 61.7%. Among the biological controls, the best control was noted for treatments combining the antibiotic streptomycin with a product based on Pantoea agglomerans (55.0% mean disease reduction) or Bacillus subtilis (53.9%). Mean disease control was 31.9, 25.7, and 22.6%, respectively, for products based on B. subtilis, Pantoea agglomerans, and Pseudomonas fluorescens without an antibiotic, suggesting that the higher efficacy of the combination treatments was due to the antibiotic. Among the plant defense-activating products, prohexadione calcium had the highest and most consistent effect size (50.7% control), while other products provided modest mean disease control of between 6.1 and 25.8%. Percent control values were significantly moderated by study location and cultivar used in the study, and were smaller, but more variable, when products were tested under high disease intensity compared with low disease intensity. Results indicate that wide-scale use of biological control and plant defense-activating products in the eastern United States is likely to remain low.

scholarly journals Efficacy of Different Fungicides Against Rhizome Rot Disease of Ginger Under Farmer Field Condition in Salyan, Nepal

2021 ◽  
Vol 6 (6) ◽  
Author(s):  
Resham B ◽  
◽  
Amrita P ◽  
Anish P ◽  
Bikash G ◽  
...  
Keyword(s):  
Field Experiment ◽  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Trichoderma Viride ◽  
Germination Percentage ◽  
Tiller Number ◽  
Leaf Number ◽  
Rot Disease ◽  
Rhizome Rot

A study was conducted from March to August 2020 to evaluate the effectiveness of different fungicides for the management of rhizome rot disease in ginger. The field experiment was conducted under Randomized Complete Block Design with four replication and five treatments; Carbendazim 50% WP @ 1gm/litre + Mancozeb 75% WP @ 2.5gm/litre, Metalaxyl 8% WP + Mancozeb 64% WP @ 2gm/litre, Carbendazim 50% WP @ 1gm/litre, Trichoderma viride @ 5gm/litre and control. The height of pseudo stems, leaf number, germination percentage, tiller number, disease incidence, disease severity and percentage of disease control was recorded during field experiment. There was no significant effect of pre sowing rhizome treatment in height of pseudostems, leaf number and germination percentage. The highest tiller number (3.40) was found with Carbendazim 50% WP @1gm/litre + Mancozeb 75% @ 2.5gm/ litre treatment and lowest tillers number (2.95) was found with control. The highest disease incidence (34.37) and severity (30.03) was found in control plot whereas the lowest disease incidence (2.58) and disease severity (2.46) was found with Carbendazim 50% @ 1gm/litre treatment + Mancozeb 75% @ 2.5gm/litre. Similarly, the highest percentage disease control (85.61) was found with Carbendazim 50% @ 1gm/litre + Mancozeb 75% @ 2.5gm/litre treated rhizome and the lowest (54.14) was found with Trichoderma viride @ 5gm/litre treatment. Therefore, seed treatment with Carbendazim 50%WP @ 1gm/litre + Mancozeb 75% WP @ 2.5 gm/litre is found effective among other fungicides in Bagchaur-3, Salyan and is recommended for enhancing tiller and reducing rhizome rot disease incidence and severity in ginger.

scholarly journals Management of Fire Blight Using Pre-bloom Application of Prohexadione-Calcium

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1048-1054
Author(s):  
Anna E. Wallis ◽  
Kerik D. Cox
Keyword(s):  
New York ◽  
Tree Growth ◽  
Cell Walls ◽  
Fire Blight ◽  
Shoot Growth ◽  
New York State ◽  
Bacterial Disease ◽  
Cortical Parenchyma ◽  
Shoot Blight ◽  
Prohexadione Calcium

Fire blight, a bacterial disease of rosaceous plants caused by Erwinia amylovora, is one of the most important diseases affecting commercial apple production worldwide. Antibiotics, applied at bloom to protect against blossom infection, are the most effective means of management but raise concern due to the potential for antibiotic resistance in both the pathogen population and nontarget organisms. In addition, most fire blight outbreaks in New York State often emerge in late June to July as shoot blight, calling into question the role of blossom infections and the antibiotic applications made to manage them. Prohexadione-calcium (PhCa) is a gibberellic acid inhibitor used post-bloom to control shoot vigor and to manage shoot blight. However, the magnitude of shoot blight management is directly related to the suppression of shoot growth, which is undesirable, especially in young orchards during establishment years. PhCa is believed to control shoot blight by thickening cell walls in cortical parenchyma, preventing invasion of host tissues by E. amylovora. We hypothesize that PhCa applied pre-bloom could similarly prevent invasion of blossom pedicels following infection, leading to reduced disease incidence. We evaluated novel pre-bloom PhCa programs for their effects on disease management (blossom and shoot blight) as well as their impact on shoot growth for three years in a mature ‘Gala’ orchard in New York. In all three years of the study, all PhCa programs resulted in less than 27% incidence (71% control) of blossom blight and less than 13% incidence (77% control) of shoot blight with minimal effect on tree growth. Inclusion of a biopesticide during bloom further reduced the incidence of blossom blight in one year of three. Using light microscopy, we found that cell walls in the cortical parenchyma of fruitlet pedicels on trees receiving pre-bloom PhCa applications were significantly thicker than those of untreated trees 40 days after full bloom and inoculation. Overall, we found that pre-bloom applications of PhCa had utility in reducing blossom blight and shoot blight with minimal impacts on tree growth. These pre-bloom programs would fit with standard production practices and may contribute toward the development of fire blight management programs without the use of antibiotics.

Effect of the addition of a fungicide to glyphosate applied postemergence on crop injury, disease control, and corn yield

2018 ◽  
Vol 98 (4) ◽  
pp. 971-974 ◽  
Author(s):  
Nader Soltani ◽  
David C. Hooker ◽  
Jonathan Brinkman ◽  
Peter H. Sikkema
Keyword(s):  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Corn Yield ◽  
Corn Production ◽  
Crop Injury

The addition of pyraclostrobin, pyraclostrobin/fluxapyroxad, pyraclostrobin/metconazole, trifloxystrobin/propiconazole, azoxystrobin/propiconazole, and trifloxystrobin/prothioconazole fungicides to glyphosate reduced disease incidence up to 19% and disease severity up to 4% compared with glyphosate alone. Fungicides evaluated can be safely mixed with glyphosate for corn production, but fungicide use was not associated with increased corn yield.

scholarly journals Disease Incidence on Old Garden Roses in the South

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 590A-590
Author(s):  
Beth Clendenen ◽  
B.K. Behe ◽  
K.L. Bowen
Keyword(s):  
Disease Resistance ◽  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Natural Resistance ◽  
Treatment Control ◽  
Diplocarpon Rosae ◽  
Significant Incidence ◽  
Overall Performance ◽  
Rain Events

Eleven rose cultivars were field planted and evaluated weekly for disease, defoliation, and overall vigor in order to compare natural resistance to blackspot (Diplocarpon rosae). Alternative treatments were also compared for efficacy in low-maintenance disease control. Treatments included a bimonthly application of chlorothalonil, a bimonthly application of a horticultural oil, an application of chlorothalonil based on rain events, and a no-treatment control. Cultivars showed significant differences in disease severity, defoliation, and overall performance, with old garden rose varieties showing more natural disease resistance than modern susceptible varieties included in the study. Chlorothalonil applied on a 14-day spray schedule did provide a significant decrease in blackspot disease severity when compared to other treatments. A significant incidence of secondary disease including Cercospora rosicola and Botrytis cinerea occurred on old garden rose varieties. No treatment differences were found for these diseases. `Belinda's Dream', `The Fairy', and `Red Mediland' ranked highest in overall performance throughout the season.

scholarly journals Effect of Cultural and Biological Treatments in Managing Clubroot Disease of Cabbage in Sidhuwa, Nepal

2019 ◽  
Vol 7 (1) ◽  
pp. 96-101
Author(s):  
Ashish Ghimire ◽  
Sundarman Shrestha
Keyword(s):  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Block Design ◽  
Combined Treatment ◽  
Severity Index ◽  
Disease Severity Index ◽  
Effective Microorganisms ◽  
Clubroot Disease ◽  
Biological Treatments

The Plasmodiophora brassicae Woronin is an important soil pathogen that attacks brassicaceae family of plants. The ability of pathogen to survive in soil for many years as a resting structure even in the absence of suitable host has increased its threat by making it more devastating. Lower effectiveness of treatments applied so far and failure to completely eradicate the disease once it enters the field has posed more problems. The study was conducted at a disease infected field in Sidhuwa, Dhankuta. It was focused on the effectiveness of different cultural and biological treatments against clubroot disease under field conditions. The treatments; lime, combination of lime and vermicompost, Effective Microorganisms (EM) solution and Trichoderma viride were arranged in Randomized Complete Block Design and replicated four times. The yield and yield attributing parameters and clubroot scale were recorded at the time of harvest. Values like Disease Incidence, Disease Severity Index and Disease Control Percentage were calculated based on clubroot scale value. The treatments showed no significant influence on vegetative parameters of the plants and on disease incidence. However, the combined treatment of lime and vermicompost was found to be most effective regarding disease severity and disease control i.e. the least Disease Severity Index (31.25%) and highest Disease Control Percentage (50.94%) compared to the control were obtained from the combined treatment of lime and vermicompost. Effective Microorganisms showed the highest disease severity. The combination of lime and vermicompost used as a treatment yielded highest marketable head weight (1.779 kg) and head diameter (19.90 cm). Int. J. Appl. Sci. Biotechnol. Vol 7(1): 96-101

scholarly journals Effect of Prohexadione-Calcium Dose Level on Shoot Growth and Fire Blight in Young Apple Trees

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1099-1106 ◽  
Author(s):  
J. L. Norelli ◽  
S. S. Miller
Keyword(s):  
Fire Blight ◽  
Shoot Growth ◽  
High Dose ◽  
Apple Orchards ◽  
Calcium Treatment ◽  
Apple Trees ◽  
Resistance Response ◽  
Treatment Dose ◽  
Prohexadione Calcium ◽  
Young Apple

Prohexadione-calcium suppresses both shoot growth and fire blight in apple. In young apple orchards, there are conflicting requirements to control fire blight and allow sufficient tree growth for tree establishment. Application of prohexadione-calcium to various cultivars of orchard-grown apple trees ranging in age from newly planted to fifth-leaf trees indicated that fewer high-dose (125 or 250 mg ·liter-1) applications of prohexadione-calcium provided a better balance between fire blight control and growth in young orchards than multiple low-dose (30 or 63 mg·liter-1) applications. The response of early-season shoot growth to prohexadione-calcium treatment dose was linear. However, trees that received high doses of prohexadione-calcium tended to grow more in the latter part of the season, resulting in little or no difference in total seasonal growth between trees that received a few high or multiple low doses of prohexadione-calcium. Enhancement of fire blight resistance by prohexadione-calcium was correlated with shoot growth suppression at the time of inoculation, and the resistance response to prohexadione-calcium treatment dose was linear. Fire blight management strategies that use prohexadione-calcium in young apple orchards are discussed.

scholarly journals The effect of Regalis® (prohexadione calcium) on the reduction of fire blight (Erwinia amylovora) severity in apple trees

2004 ◽  
Vol 10 (2) ◽  
Author(s):  
P. Sobiczewski ◽  
T. Bubán
Keyword(s):  
Active Ingredient ◽  
Fire Blight ◽  
Shoot Growth ◽  
Control Strategies ◽  
Fruit Trees ◽  
Pome Fruit ◽  
Apple Trees ◽  
Obvious Effect ◽  
One Year ◽  
Prohexadione Calcium

Due to the lack of effective and non-phytotoxic materials for control of the blossom and shoot blight phase of fire blight in pome fruit trees, two novel control strategies have emerged: shoot growth retardation by bioregulators and applying resistance inducer compounds. Prohexadione calcium (ProCa) is the active ingredient of the bioregulator Regalis® registered in several European countries. The reduction of shoot growth elongation is the most obvious effect of ProCa. Furthermore, it causes significant changes in the spectrum of flavonoids and their phenolic precursors, leading to the considerable reduction of susceptibility to fire blight. In Poland, potted one-year-old apple trees of cvs. Gala Must grafted on M.26 and Sampion on M.9 (in 2001) as well as Gala Must on P.60 (in 2002) were treated with Regalis® at a range of concentration of 250, 150 or 150 + 100 ppm, respectively. The inoculation of shoots was made with the strain No.691 of E. amylovora (107 cfu/ml), on the 7th and 21st'day after treatments with Regalis. In Hungary, during the years of 2002 and 2003 one-year-old container grown apple trees of the cvs. Idared/M.9 and Freedom/M.9 were treated with the prohexadione-Ca, the active ingredient of Regalis® 100, 150 or 200 ppm, two weeks before inoculation with the Ea 1 strain of E. amylovora (107 cfu/m1). In Poland, the suppression of fire blight in shoots reached up to 80%, depending on concentration and application time of Regalis®. In Hungary, the effect of prohexadione-Ca treatments, determined by the length of necrotic lesion developed, proved to be better than that of streptomycin used for comparison.

scholarly journals Plant extracts for controlling the post-harvest anthracnose of banana fruit

2013 ◽  
Vol 15 (4 suppl 1) ◽  
pp. 727-733 ◽  
Author(s):  
M.E.S. Cruz ◽  
K.R.F. Schwan-Estrada ◽  
E. Clemente ◽  
A.T. Itako ◽  
J.R. Stangarlin ◽  
...  
Keyword(s):  
Essential Oil ◽  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Fruit Rot ◽  
Control Treatment ◽  
Distilled Water ◽  
Banana Fruit ◽  
Efficient Treatment ◽  
Post Harvest

In banana, fruit rot is incited by Colletotrichum musae which has been the most serious post-harvest disease of immature and mature fruit. The usual control by fungicides prohibited in many countries reduces their commercial value. Therefore, two experiments were conducted to evaluate the antimicrobial activity of alternative products to the synthetic fungicides. First, berries naturally infected by anthracnose were immersed into Azadirachta indica and citric extracts at 2 and 4% (v/v) for 3 minutes and stored for 11 days under environmental conditions. Next, other berries were immersed into essential oil emulsions of Allium sativum, Copaifera langsdorfii, Cinnamomum zeylanicum and Eugenia caryophyllata at 5% for 3 minutes but stored for 11 days. Berries immersed into distilled water were used as control-treatments. The percentage of disease incidence observed in the control-treatment was similar to the ones observed in the extract of A. indica at 2%. The control-treatment showed disease severity of 75.13% and the percentage of disease control was 20.85%. Fruit immersed into distilled water presented less effectiveness than the ones immersed into citric extracts, which promoted the highest effectiveness. Citric extract at 4% was the most efficient treatment because the disease incidence was 19.44%, the disease severity was 9.34% and the disease control was 90.16%. Less severity and, consequently, more disease control were achieved by immersing the berries into the emulsion of essential oil of A. sativum, followed by treatments with C. langsdorfii, E. caryophyllata and C. zeylanicum.

scholarly journals Evaluation of fungicides for management of anthracnose disease of black gram (Vigna mungo l.) in growing areas of district Jhansi of Bundelkhand region

2020 ◽  
Vol 12 (2) ◽  
pp. 110-114
Author(s):  
Adesh Kumar ◽  
Roomi Rawal ◽  
Nishi Roy ◽  
Atik Ahamad ◽  
Hitesh Kumar
Keyword(s):  
Disease Control ◽  
Disease Severity ◽  
Field Condition ◽  
Seed Treatment ◽  
Disease Incidence ◽  
Foliar Spray ◽  
Uttar Pradesh ◽  
Vigna Mungo ◽  
Black Gram ◽  
Anthracnose Disease

Black gram (Vigna mungo L.) growing areas of district Jhansi coming under Bundelkhand region of Uttar Pradesh were surveyed during Kharif 2018 for the occurrence of anthracnose disease of black gram. A total of 22 villages were visited under six blocks of Jhansi during this period. Blockwise comparison of the survey in Jhansi revealed that less mean disease incidence (10%) and severity (4.0%) occurred in the Chirgaon block. Highest disease incidence (24%) and severity (12%) were observed in block Moth.  The block Bangra, Babina, Badagaon, and Bamour secured disease incidence 23.5, 20, 16.44 and 15% and severity 15.14, 12, 7.44 and 8.5% respectively. Nine fungicides (viz. [email protected]%, tilt @0.1%, [email protected]%, [email protected]%, [email protected]%, dithane [email protected]%, amistar top, [email protected]% and [email protected]%) were tested against anthracnose disease of black gram under field condition.  Among them, seed treatment with carbendazim@ 3gram/kg seed and foliar spray of mixture of azole and strobilurin group T3- [email protected] ( tebuconazole + trifloxystrobin) and T7-amistar [email protected]%  (azoxystrobin+ difenoconazole) were found significantly (at 0.05%) superior over the rest of treatments, both showed minimum (6%) disease severity with maximum (78.51%) disease control. Significant (at 0.05%) increase in yield (47.5%) also observed in both treatments T3 and T7.  The treatment T1- Spray of  [email protected]%, T2-  Spray of  Tilt @0.1%, T4- Spray of  [email protected]%, T5- Spray of  [email protected]%,  T8- Spray of [email protected]%, T9- Spray of [email protected]% also showed good results in reducing the black gram anthracnose disease severity per cent (64.29, 57.14, 64.28, 57.14, 71.42 and 64.28 and also increased the yield per cent 37.5, 35, 42.5, 36.25, 45 and 45 respectively.

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