scholarly journals Evaluation of Biological Agents for Control of Macrophomina Root Rot and Powdery Mildew in Flowering Dogwood (Cornus florida L.)

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1461-1466
Author(s):  
Margaret T. Mmbaga ◽  
Lucas M. Mackasmiel ◽  
Frank A. Mrema
Keyword(s):  
Powdery Mildew ◽  
Plant Growth ◽  
Root Rot ◽  
Plant Root ◽  
Macrophomina Phaseolina ◽  
Stem Length ◽  
Growth Enhancement ◽  
Cornus Florida ◽  
Bacterial Isolates ◽  
Flowering Dogwood

Six biological control agents (BCAs) (two bacteria, two fungi, and two yeasts) that were previously shown to be effective against powdery mildew (Erysiphe pulchra) were tested for efficacy against Macrophomina phaseolina root rot on flowering dogwood (Cornus florida) in the greenhouse. Two of the bacterial isolates, Stenotrophomonas sp. (B17A) and Serratia sp. (B17B), were effective in controlling both macrophomina root rot and powdery mildew, similar to fungicide control thiophanate methyl, when roots were drenched with the six BCAs individually. In addition, the two bacterial BCAs improved plant growth with respect to stem diameter, stem length, dry weight, and green foliage compared with fungicide-treated plants or nontreated controls grown in sterile soil. These results confirm previous results in which B17A and B17B suppressed powdery mildew and also promoted plant growth in flowering dogwood. Although macrophomina root rot has been previously reported as a potential problem in flowering dogwood, especially in field conditions, simultaneous infection with macrophomina root rot and powdery mildew has not been previously reported. This study confirmed that M. phaseolina infection was characterized by stubby roots and black root lesions, and plants infected with both powdery mildew and macrophomina root rot had smaller root mass compared with fungicide-treated plants. Neither of the two pathogens killed their host plants, but compounded infections significantly reduced the plant root system and plant growth. The efficacy of the two bacterial isolates in controlling both powdery mildew and macrophomina root rot suggests their potential utilization in controlling both diseases in dogwood nursery production and in other plants that are hosts to both powdery mildew and macrophomina root rot. Plant growth promoted by the two BCAs may be attributed to powdery mildew and macrophomina root rot control, but comparisons between fungicide-treated plants and control plants not inoculated with BCAs or root rot pathogen suggested that the two BCAs may play a role as bio-stimulants in growth enhancement. These results also suggest that the two biocontrol agents are not phytotoxic to dogwood.

scholarly journals Isolation, Morphological and Biochemical Characterization of Rhizobacteria from Arsenic Contaminated Paddy Soils in Bangladesh: An In vitro Study

2021 ◽  
pp. 41-55
Author(s):  
M. M. Hossain ◽  
G. K. M. M. Rahman ◽  
M. A. M. Akanda ◽  
A. R. M. Solaiman ◽  
M. T. Islam ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Phosphate Solubilization ◽  
Cellulose Degradation ◽  
Paddy Soils ◽  
Growth Enhancement ◽  
Bacterial Isolates ◽  
Plant Growth And Development ◽  
Iaa Production

Soil-plant–microbes relations within the plant rhizosphere are the determinants of plant and soil health, which is important for soil ecological environment for plant-microbe interactions. Plant growth-promoting rhizobacteria (PGPR) are considered to encourage plant growth and development directly or indirectly in soil. PGPR can demonstrate a diversity of characteristics responsible .for influencing plant growth and development. During this study, Twenty four different bacterial isolates were isolated, and detailed morphological, biochemical, and physiological characterizations of those isolates were accomplished. This experiment was performed with the 24 bacterial isolates to see their gram stain test, KOH test, catalase activity, cellulose degradation capability, in dole acetic acid (IAA) production, and phosphate solubilization activities, and also tested for growth within the different arsenic and salt stress conditions and 37°C temperature. Results revealed that among the rhizobacterial isolates, fifteen bacterial isolates were negative and nine was positive in gram reaction, while some were showed high IAA production ability, phosphate solubility capability, and cellulose degradation capacity within the culture media. The isolates were isolated from paddy soils and a few were characterized by a yellow color, flat elevation, and gram-positive, while some were characterized because of the yellowish color with round colony shape, raised elevation, gram-negative, and every one the isolates were positive in catalase production capacity and phosphate solubilization activity which is able to increase the available phosphorus within the soil for plants and also produced indole acetic acid that may use as a hormone to be used in growth enhancement of plants. Hence, these isolates need to be tested further for their effect on arsenic dynamics at the plant rhizosphere, selection of suitable plant species for the bacterial association, bacterial effect on arsenic uptake by plants, and potentials for field applications for sustainable agriculture.

Development ofErysiphe pulchra, the causal agent of powdery mildew, on leaf disks of susceptible and resistant flowering dogwood (Cornus florida)

2006 ◽  
Vol 28 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Y. H. Li ◽  
M. T. Windham ◽  
R. N. Trigiano ◽  
D. C. Fare ◽  
J. M. Spiers ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Causal Agent ◽  
Cornus Florida ◽  
Flowering Dogwood ◽  
Leaf Disks

scholarly journals Prunus mahaleb Seedling Populations as Improved Rootstocks for Sweet Cherry

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 618c-618
Author(s):  
F.A. Bliss ◽  
Ali A. Almehdi
Keyword(s):  
Powdery Mildew ◽  
Plant Growth ◽  
Root Rot ◽  
Crown Gall ◽  
Pollen Fertility ◽  
Sweet Cherry ◽  
Nursery Stock ◽  
Prunus Mahaleb ◽  
Cherry Rootstocks ◽  
And Control

Seedlings of Prunus mahaleb are often used as rootstocks for sweet cherry (P. avium) scion cultivars in commercial orchards. While they are desirable based on ease of propagation and economical production of nursery stock, seedlings may be variable resulting in nonuniform compound trees, and they are susceptible to several important diseases. Seedling sources have shown substantial variability for population uniformity of plant growth, and reaction to crown gall, powdery mildew and Phytophthora root rot. Segregating families also vary for pollen fertility, inbreeding response and control of scion growth. Multiple screening for favorable trait combinations is underway to develop improved sources of cherry rootstocks.

scholarly journals ‘Appalachian Joy’ is a Supernumerary, White-bracted Cultivar of Flowering Dogwood (Cornus florida) Resistant to Powdery Mildew (Erysiphe pulchra)

HortScience ◽  
2016 ◽  
Vol 51 (5) ◽  
pp. 592-594 ◽  
Author(s):  
Robert N. Trigiano ◽  
Alan S. Windham ◽  
Mark T. Windham ◽  
Phillip A. Wadl
Keyword(s):  
Powdery Mildew ◽  
Cornus Florida ◽  
Flowering Dogwood

Management of powdery mildew in flowering dogwood in the field with biorational and conventional fungicides

2004 ◽  
Vol 84 (3) ◽  
pp. 837-844 ◽  
Author(s):  
M. T. Mmbaga ◽  
R. J. Sauvé
Keyword(s):  
Powdery Mildew ◽  
Copper Sulfate ◽  
Management Program ◽  
Environmental Benefits ◽  
Potassium Bicarbonate ◽  
Cornus Florida ◽  
Thiophanate Methyl ◽  
Flowering Dogwood ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate

In a 2 yr study, control of powdery mildew on flowering dogwood (Cornus florida L.) by four biorational and four conventional fungicides was assessed on seedlings and on 3 yr liners in the field. Biorational fungicides applied were three household soaps containing 0.2% triclosan (Irgasan® DP 300)—Ajax® liquid hand soap, Equate® liquid dish soap and Palmolive® liquid dish soap-and potassium bicarbonate salt. Conventional fungicides applied were propiconazole, thiophanate methyl, azoxystrobin and copper sulfate pentahydrate. All products controlled powdery mildew compared with water controls. Application of the biorational fungicides on a weekly basis was as effective as propiconazole and thiophanate methyl and more effective than azoxystrobin and copper sulfate pentahydrate. Application of some biorational products at semi-monthly intervals was slightly less effective. Of the biorational fungicides, Palmolive® was the most effective but was phytotoxic, whereas Ajax®, Equate® and potassium bicarbonate were not. When three applications of any biorational fungicide were rotated with one application of propiconazole, the incidence of powdery mildew was less than when a fungicide rotation was not included. Plant growth was enhanced with either biorational or conventional fungicides compared with water controls. Propiconazole treatments resulted in the highest growth rates, whereas biorational products were as effective in promoting growth as thiophanate methyl, azoxystrobin or copper sulfate pentahydrate. The incorporation of biorational fungicides in a powdery mildew disease management program may have economic and environmental benefits because they are less costly than conventional fungicides and presumed safer to the environment and the applicators. Key words: Cornus florida L., Erysiphe (sect. Microsphaera) pulchra, Microsphaera pulchra, Oidium spp, Phyllactinia guttata

scholarly journals Susceptibility of Cultivars of Several Dogwood Taxa to Powdery Mildew and Spot Anthracnose

1998 ◽  
Vol 16 (3) ◽  
pp. 147-151 ◽  
Author(s):  
A. K. Hagan ◽  
B. Hardin ◽  
C. H. Gilliam ◽  
G. J. Keever ◽  
J. D. Williams ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Cornus Florida ◽  
Flowering Dogwood

Abstract Incidence of powdery mildew (Microsphaera penicillata) and spot anthracnose (Elsinoe corni) was assessed on 37 selections or cultivars of flowering dogwood (Cornus florida), kousa dogwood (C. kousa), hybrid dogwood (C. kousa x florida and C. nuttallii x florida) and giant dogwood (C. controversa). Across all cultivars, the flowering dogwood and C. nuttallii x florida ‘Eddie's White Wonder’ are more susceptible to powdery mildew and spot anthracnose than the kousa, C. kousa x florida hybrids and giant dogwood. Among the cultivars of flowering dogwood screened, ‘Cherokee Brave’, ‘Cherokee Chief’, ‘Welch's Bay Beauty’ and ‘Weaver's White’ were partially to highly resistant to both diseases. With few exceptions, the kousa dogwood and C. kousa x florida hybrids, and giant dogwood suffered very little powdery mildew or spot anthracnose-related damage.

scholarly journals Disease Resistance and Adaptability of Stellar and Flowering Dogwood Cultivars at Two Alabama Sites

2011 ◽  
Vol 29 (4) ◽  
pp. 169-174
Author(s):  
A.K. Hagan ◽  
J.R. Akridge ◽  
J. Ducar ◽  
K.L. Bowen
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Ambrosia Beetle ◽  
Insect Damage ◽  
Cornus Florida ◽  
Cercospora Leaf Spot ◽  
Flowering Dogwood ◽  
Southern States ◽  
Synanthedon Scitula ◽  
Dogwood Borer

Abstract Stellar® dogwood (Cornus florida × kousa) cultivars Aurora®, Constellation®, Celestial™, Ruth Ellen®, and Stellar Pink® were compared with selected flowering dogwood (Cornus florida) cultivars Cherokee Brave®, ‘Cherokee Princess’, ‘Cloud 9’, and ‘Rubra’ in a simulated landscape planting at sites in southwest (USDA Hardiness Zone 8a) and northeast Alabama (USDA Hardiness Zone 7a) for their reaction to the diseases spot anthracnose, powdery mildew, and Cercospora leaf spot. Tree longevity as influenced by the occurrence of the dogwood borer (Synanthedon scitula) and an ambrosia beetle (Xylosandrus sp.) was also assessed at both sites. All Stellar® dogwood cultivars generally proved resistant to the bract and leaf spot phases of spot anthracnose as well as powdery mildew and Cercospora leaf spot. While Cherokee Brave® was the only flowering dogwood with partial resistance to powdery mildew at both sites; this and the other flowering dogwood cultivars were equally susceptible to spot anthracnose and Cercospora leaf spot. Insect damage levels were higher at the southwest site than the northeast Alabama site. Within 3 years of establishment at the southwest Alabama site, incidence of tunneling damage attributed to dogwood borer and an ambrosia beetle was higher on the Stellar® dogwood than flowering dogwood cultivars, which also had higher values for tree longevity. In contrast, tree longevity was equally high and insect damage equally low at the northeast Alabama site for both the Stellar® and flowering dogwood cultivars. Superb resistance to the diseases spot anthracnose, powdery mildew, and Cercospora leaf spot translated into superior aesthetics and fall color for the Stellar® compared with the flowering dogwood cultivars at the northeast Alabama site. Hardiness of Stellar® dogwood cultivars in Alabama and possibly other southern states below USDA Hardiness Zone 7a is questionable due to tree vulnerability to the dogwood borer and ambrosia beetle.

scholarly journals Accumulation of a Protein Associated with Plant Defense in Powdery Mildew Resistant Dogwood (Cornus florida)

2006 ◽  
Vol 24 (2) ◽  
pp. 115-118
Author(s):  
M.T. Mmbaga ◽  
F.J. Avila ◽  
E.F. Howard ◽  
E.L. Myles
Keyword(s):  
Powdery Mildew ◽  
Plant Defense ◽  
Powdery Mildew Resistance ◽  
Cornus Florida ◽  
Defense Proteins ◽  
Mildew Resistance ◽  
Flowering Dogwood ◽  
Plant Defense Proteins ◽  
Powdery Mildew Pathogen ◽  
High Level

Abstract This study was conducted to better understand the nature of powdery mildew resistance in flowering dogwood (Cornus florida L.) and in particular to determine if inducible plant defense proteins are associated with powdery mildew resistance. Results from this study showed an accumulation of a new protein in resistant plants, but not in susceptible plants that were challenged with powdery mildew pathogen (Erysiphe (Sect. Microsphaera) pulchra). The protein accumulated in a high level in the resistant selections at 48 hr after inoculation with the pathogen and that was consistent with the production of pathogenesis related (PR) proteins. The protein was characterized as having an isoelectric point of 7.5 ± 0.5 and molecular weight of 18 ± 2 KD. Partial sequence analysis of this protein revealed homology with PR-10 protein associated with drought resistance in potato and was analogous to other proteins related to resistance in other crops. Repeated analysis showed similar results and suggested that a biochemical mode of resistance involving plant defense proteins may be associated with powdery mildew resistance in flowering dogwood.

scholarly journals Naturally Occurring Resistance to Powdery Mildew in Seedlings of Cornus florida

1998 ◽  
Vol 16 (3) ◽  
pp. 173-177 ◽  
Author(s):  
Mark T. Windham ◽  
Willard T. Witte
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Resistance Mechanisms ◽  
Cornus Florida ◽  
Field Surveys ◽  
Flowering Dogwood ◽  
Naturally Occurring ◽  
High Incidence ◽  
Low Levels ◽  
Symptoms And Signs

Abstract Two production nursery fields of flowering dogwood, Cornus florida L., seedlings with a high incidence of powdery mildew were surveyed for plants free of symptoms and signs of the disease. In greenhouse trials most of the seedlings selected in the field survey for being free of powdery mildew were found to be escapes (had no disease resistance) or to exhibit partial resistance (unacceptable low levels of resistance). In those trials, twenty seedlings, representing approximately 0.1% of the seedlings examined in the field surveys, displayed resistance to powdery mildew similar to that of C. florida ‘Cherokee Brave’. This group of disease resistant seedlings will be used to develop new cultivars of white flowering dogwood resistant to powdery mildew and to investigate the inheritance of powdery mildew resistance mechanisms in flowering dogwood.

scholarly journals First Report of the Teleomorph of an Oidium sp. Causing Powdery Mildew on Flowering Dogwood in South Carolina

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 200-200 ◽  
Author(s):  
M. R. Williamson ◽  
J. H. Blake
Keyword(s):  
South Carolina ◽  
Powdery Mildew ◽  
Morphological Features ◽  
Minor Importance ◽  
Cornus Florida ◽  
First Report ◽  
Flowering Dogwood ◽  
Young Leaves ◽  
First Time ◽  
Leaf Symptoms

Prior to 1994, powdery mildew had rarely been reported on flowering dogwood (Cornus florida) in the southeastern U.S. That year, and every year since, epiphytotics of powdery mildew have occurred. Leaf symptoms include distortion and necrotic areas on young leaves and an increase in red pigmentation surrounding infection sites. Young seedlings may be stunted by this disease and growth of older trees may be slowed (2). In early November, 1996, dogwood (C. florida) trees at 10 locations each in Anderson, Oconee, and Pickens counties in northwestern South Carolina were surveyed for the presence of powdery mildew. Leaves with signs of powdery mildew (white, powdery patches of mycelium, conidiophores, and conidia) were examined with a ×10 hand lens and leaves with cleistothecia were collected and taken back to the laboratory. Numerous leaves from each site were first examined at ×50 on a dissecting microscope to observe gross morphological features of cleistothecia. Then, approximately 10 cleistothecia from each of two sites were examined on a compound microscope at ×100 or higher to make further observations and measurements. Cleistothecial diameter ranged from 75.0 to 92.5 μm (average 81.8 μm). Appendages, which averaged 6 to 11 per cleistothecium, were 110 to 140 μm long (average 125.7 μm) or 1.54 times the cleistothecial diameter. The apices of appendages were dichotomously branched 2 to 3 times and the tips were distinctly re-curved. The stalks were aseptate and hyaline. Cleistothecia contained 3 to 5 asci. Each ascus contained 2 to 6 ascospores measuring 18 to 28 × 13 to 15 μm. Based on these characteristics, the teleomorph was tentatively identified as Microsphaera pulchra. Cleistothecia were found to be slightly smaller and the number of appendages fewer than Braun's lectotype (1), but these differences were judged to be of minor importance. Therefore, we conclude that the teleomorph of the Oidium sp., herein reported on flowering dogwood for the first time in South Carolina, is Microsphaera pulchra References: (1) U. Braun. Nova Hedwigia 89:1, 1987. (2) L. A. Klein et al. Plant Dis. 82:383, 1998.

Sign in / Sign up

Export Citation Format

Share Document