scholarly journals Biological control of watermelon seedling blight caused by Acidovorax citrulli using antagonistic bacteria from the genera Curtobacterium, Microbacterium and Pseudomonas

2018 ◽  
Vol 54 (No. 3) ◽  
pp. 138-146 ◽  
Author(s):  
Horuz Sumer ◽  
Aysan Yesim
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Eastern Mediterranean ◽  
Disease Incidence ◽  
Eastern Mediterranean Region ◽  
Dual Culture ◽  
Antagonistic Bacteria ◽  
Seedling Blight ◽  
Acidovorax Citrulli ◽  
Microbacterium Oxydans

The biological control of the watermelon seedling blight and fruit blotch disease was investigated by screening the potential use of antagonistic bacteria. Between May and August 2012, totally 322 putative antagonistic bacteria were isolated from symptomless melon and watermelon plants grown in Adana, Hatay, and Osmaniye provinces of the Eastern Mediterranean Region of Turkey. In vitro dual culture tests showed that 54 out of 322 strains inhibited the Acidovorax citrulli (Ac) growth with an appearance of clear zones between 2.3 and 27.0 mm in diameter. However, the remaining 268 strains did not exhibit any antagonistic activity against Ac. Seed treatments with fourteen individual antagonistic bacteria resulted in a significant reduction in disease incidence (DI) and severity (DS) ranging between 14.06–79.47% and between 4.57–41.49%, respectively. The bacteria Pseudomonas oryzihabitans (Antg-12), Microbacterium oxydans (Antg-57), Curtobacterium flaccumfaciens (Antg-198), and Pseudomonas fluorescens (Antg-273) were the most potent antagonistic bacterial isolates which reduced DI and DS as compared to the untreated control. This study suggested the potential of bacterial antagonists Curtobacterium flaccumfaciens, Microbacterium oxydans, Pseudomonas oryzihabitans, and Pseudomonas fluorescens for the biocontrol of Ac-induced bacterial fruit blotch (BFB).

scholarly journals Occurrence, isolation, and identification of Acidovorax citrulli from Melon in Turkey

2014 ◽  
Vol 50 (No. 4) ◽  
pp. 179-183 ◽  
Author(s):  
S. Horuz ◽  
R. Cetinkaya-Yildiz ◽  
M. Mirik ◽  
Y. Aysan
Keyword(s):  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Isolation And Identification ◽  
New Host ◽  
Causal Organism ◽  
Plant Materials ◽  
Small Water ◽  
Acidovorax Citrulli ◽  
Initial Symptoms ◽  
Production Areas

During February and August of 2010 and 2011, disease symptoms were detected in melon (Cucumis melo cv. Surmeli) fields and commercial nurseries in Adana and Mersin provinces (Eastern Mediterranean Region, Turkey). Lesions on leaves and fruits were observed in nearly 75 and 85 acres production areas of melon in 2010 and 2011, respectively. Initial symptoms were water-soaked irregular spots, light brown to reddish spots advancing through veins on leaves, small water-soaked lesions, greasy, dark olive green colour areas on the surfaces of melon fruit followed by brown lesions, softening, and cracks. Thirty-five non-fluorescent, slow-growing, round, cream and Gram-negative bacterial isolates were isolated from symptomatic plant materials. The pathogenicity of the isolates was proved using melon seedlings and fruits. According to classical, serological, and molecular assays, the causal organism was identified as Acidovorax citrulli. To the best of our knowledge, this is the first report and occurrence of bacterial fruit blotch disease on melon as a new host in Turkey.  

scholarly journals Biological Control of Pear Valsa Canker Caused by Valsa pyri Using Penicillium citrinum

Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 198
Author(s):  
Hongbo Yuan ◽  
Bingke Shi ◽  
Tianxiang Huang ◽  
Zengqiang Zhou ◽  
Li Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Control Agent ◽  
Penicillium Citrinum ◽  
Lesion Length ◽  
Dual Culture ◽  
Valsa Canker

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust antifungal activity against all tested pathogens including Valsa pyri. Microscopic analyses suggested that following co-culture with ZZ1, the hyphae of V. pyri were ragged, thin, and ruptured. ZZ1 also induced significant decreases in lesion length and disease incidence on detached pear branches inoculated with V. pyri. ZZ1 isolate-derived culture filtrates also exhibited antifungal activity against V. pyri, decreasing mycelial growth and conidium germination and inhibiting V. pyri-associated lesion development on pear branches. These results suggest that the ZZ1 isolate has the potential for use as a biological control agent against V. pyri. The strain was further identified as Penicillium citrinum based on its morphological characteristics and molecular analyses. Overall, these data highlight a potentially valuable new biocontrol resource for combating pear Valsa canker.

scholarly journals Mycoparasitic nature of Egyptian Trichoderma isolates and their impact on suppression Fusarium wilt of tomato

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
A. M. Nofal ◽  
Mohamed Abd El-Rahman ◽  
T. M. Abdelghany ◽  
Mahmoud Abd El-Mongy
Keyword(s):  
Biological Control ◽  
Plant Disease ◽  
Defense Mechanism ◽  
Disease Incidence ◽  
Culture Method ◽  
Dry Weight ◽  
Protective Role ◽  
Significant Inhibition ◽  
Dual Culture ◽  
Tomato Plants

Abstract Background Plant disease administration is difficult due to the soil-borne nature of the phytopathogens. Biological control of plant disease is a safe mode to avoid the problems related to fungal diseases that affect crops productivity. Results Twenty-three Trichoderma isolates were isolated from soil, surrounding healthy tomato roots from different regions in the Egyptian Governorate of Menoufia. Using a dual culture method to test the efficiency of Trichoderma isolates, the most effective isolate identified as Trichoderma atrovirde with percentage inhibition against Fusarium oxysporum f. sp. lycopersici (92.11%) and scanning electron microscope examination documented the mycoparasitic nature of T. atrovirde to F. oxysporum. Treatments with 10% filtrate T. atrovirde improved the growth aspects of tomato plants than the control plants or infected only, as well as the increase in phenol content (15.09 ug. g-1dry weight) and decreased disease incidence percentage (8%) than the plants infected only (60%). Conclusions This study clearly demonstrated that T. atrovirde had a significant inhibition against F. oxysporum. Greenhouse assays displayed the protective role of T. atrovirde inoculation directly against pathogen or indirectly related to the defense mechanism in the plant. So, this study recommends using T. atrovirde for biological control of wilt disease in tomato plants.

scholarly journals Antagonism of Pseudomonas fluorescens from plant roots to Rigidoporus lignosus pathogen of rubber white roots in vitro

2019 ◽  
Vol 20 (6) ◽  
Author(s):  
NURHAYATI DAMIRI ◽  
MULAWARMAN MULAWARMAN ◽  
RAHIM S EFFENDI
Keyword(s):  
Pseudomonas Fluorescens ◽  
Culture Technique ◽  
Plant Roots ◽  
Dilution Method ◽  
Dual Culture ◽  
Antagonistic Bacteria ◽  
Bacterial Isolates ◽  
Rigidoporus Lignosus ◽  
Roots In Vitro

Abstract. Damiri N, Mulawarman, Effendi RS. 2019. Antagonism of Pseudomonas fluorescens from plant roots to Rigidoporus lignosus pathogen of rubber white roots in vitro. Biodiversitas 20: 1549-1554. Indonesia's rubber productivity is still relatively low. This low productivity of rubber can be caused by many factors such as the attack of Rigidoporus lignosus. This study aims to explore antagonistic bacteria from the plant roots and test their antagonism ability to R. lignosus at the laboratory level. This research was conducted at the Laboratory at the Faculty of Agriculture, Sriwijaya University, Indralaya Ogan Ilir District, South Sumatra, Indonesia. Corporate and bacterial isolations are carried out by serial dilution method. In-vitro testing of antagonistic bacteria was carried out using the dual-culture technique method on sterile PDA media by direct opposition between R. lignosus culture and antagonistic bacteria explored. Results of the study showed that a number of bacterial isolates existed there, namely 11 bacterial isolates belonging to Pseudomonas fluorescens, four from turmeric roots, three from the roots of rubber seedlings, two from galangal roots and two from the roots of yielding rubber plants. P. fluorescens from roots of turmeric, rubber seedlings, rubber, and galangal was able and had the potential to be developed as biopesticide to control R. lignosus. The best isolate in suppressing the growth and development of R. ligonosus is P. fluorescens isolates from the roots of turmeric and those of rubber seedlings (isolates of C, B, and G).

scholarly journals An Outbreak of Bacterial Stem Rot of Dieffenbachia amoena Caused by Erwinia carotovora subsp. carotovora in the Eastern Mediterranean Region of Turkey

Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 310-310 ◽  
Author(s):  
R. Cetinkaya-Yildiz ◽  
M. Mirik ◽  
Y. Aysan ◽  
M. Kusek ◽  
F. Sahin
Keyword(s):  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Disease Incidence ◽  
Eastern Mediterranean Region ◽  
Acid Methyl Ester ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Stem Rot ◽  
Tomato Plants ◽  
Rot Disease

Severe outbreaks of bacterial stem rot disease occurred on dieffenbachia plants (Dieffenbachia amoena cv. Tropic Snow) during the autumn and spring seasons of 2002 and 2003 in two commercial glasshouses (3.5 ha) near Adana and Mersin in the Eastern Mediterranean Region of Turkey. Characteristic symptoms of the disease were wilting of the lower leaves, darkening and water soaking of the leaves and stem at or below the soil level, and browning in the vessel and pith of the diseased plants. Eventually, the stem and leaves completely rotted, and the plants collapsed. Nearly 30 and 40% (2002 and 2003, respectively) of the 20,000 potted plants in the glasshouses were destroyed because of the disease. Cuttings often developed a typical soft rot during propagation. Disease incidence was estimated at approximately 50% on propagating material during 2003. Isolations were made from rotted stems, leaves, and discolored vessels of the dieffenbachia plants on King's medium B. Bacteria consistently isolated from the diseased tissues formed white-to-cream colonies on the medium. Bacteria from purified colonies were gram, oxidase, and arginine dyhidrolase negative, catalase positive, and facultative anaerobic. Ten representative strains all fermented glucose and reduced nitrates to nitrites. The strains caused soft rot of potato slices within 24 h at 25°C. All strains were resistant to erythromycin in an antibiotic disk (15 μg) assay. Negative results were obtained from utilization of α-methyl glycoside, reducing substance from sucrose, and indole production from tryptophane and phosphathase activity. Positive results were obtained from pectate, aesculin, and gelatine liquefaction for all strains. Acid was produced from glucose, sucrose, mannitol, mannose, lactose, raffinose, melibiose, trehalose, and L(+)-arabinose but not Darabinose, sorbitol, inulin, and maltose. Pathogenicity was confirmed by needle-stab inoculation at the stem on three plants each of dieffenbachia and tomato plants (5-week-old cv. H-2274). Sterile distilled water was used as a negative control. All plants were covered with polyethylene bags for 48 h at 25°C. Within 72 h after inoculation, water-soaking and soft-rot symptoms were observed on dieffenbachia and tomato plants. All of the bacterial strains isolated in the present study were identified as Erwinia carotovora subsp. carotovora (Jones) based on fatty acid methyl ester analysis with similarity indices ranging from 80 to 94%. Furthermore, Biolog GN (Department of Plant Protection, Faculty of Agriculture, Ataturk University, Erzurum, Turkey) profiles identified them as the same pathovar with similarity values of 67 to 72%. All of the test results were similar to those of reference strain GSPB 435 (Gottinger Sammlung phytopathogener Bakterien, Georg-August University, Gottingen, Germany) of E. carotovora subsp. carotovora used in this study. To our knowledge, this is the first report of the occurrence and outbreak of a bacterial rot disease on dieffenbachia grown in the Eastern Mediterranean Region of Turkey. Contaminated cuttings may be the primary source of inoculum within and between glasshouses.

scholarly journals Biological Control of Rice Brown Spot by Bacillus Spp. in Thailand

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 217
Author(s):  
Wanporn Khemmuk ◽  
Doungkamon Boonchuay ◽  
Nuchjarin Jungkhun ◽  
Chonsirin Klinmanee ◽  
Angkana Kantachan
Keyword(s):  
Biological Control ◽  
Field Experiments ◽  
Disease Incidence ◽  
Culture Technique ◽  
Brown Spot ◽  
Growth Stages ◽  
Dual Culture ◽  
Wet Season ◽  
Bipolaris Oryzae ◽  
Antagonistic Microorganisms

Rice brown spot (BS), caused by Bipolaris oryzae (Breda de Haan) Shoemaker, is a serious disease causing infection in all growth stages of rice and significantly affect to yield and grain quality losses. This study aimed to find effective antagonistic microorganisms to control BS, hundreds of microbial isolates were obtained from rice paddy fields across Thailand. A total number of 31 antagonistic microbes were selected and screened against B. oryzae by dual culture technique. The results showed that CRI_15183 has highly percentage of inhibition (67.35%) followed by ACKB03, CRI_15059, CRI_15010, No.33, CRI_15186 and BUDN027 with 57.25, 54.01, 53.28, 52.94, 52.65 and 51.26%, respectively. Then, sequencing of 16S rDNA confirmed two species of Bacillus amongst the isolates, B. subtilis and B. amyloliquefaciens. Three isolates including CRI_15183, CRI_15186 and ACKB03 were formulated with talcum based powder, stored at room temperature and sampled to test their shelf life monthly. In greenhouse experiment, the results revealed that CRI_15186 has highest effective with 14.08 percent of disease incidence followed by CRI_15183 and ACKB03 with 15.06 and 15.98%, respectively. The field experiments will be conducted in wet season this year. There have been only a few reports on the improvement of rice brown spot control involving biological control agents. However, the use of antagonistic microbes can reduced the used of fungicides and developed environmentally safe for the management of rice brown spot disease.

scholarly journals Secondary Colonization of Pear Blossoms by Two Bacterial Antagonists of the Fire Blight Pathogen

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 661-668 ◽  
Author(s):  
R. L. Nuclo ◽  
K. B. Johnson ◽  
V. O. Stockwell ◽  
D. Sugar
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Honey Bees ◽  
Fire Blight ◽  
Disease Incidence ◽  
Disease Suppression ◽  
Full Bloom ◽  
Erwinia Herbicola ◽  
Cold Temperatures ◽  
Bacterial Antagonists

Dispersal of the bacteria Pseudomonas fluorescens strain A506 and Erwinia herbicola strain C9-1S from treated to nontreated pear blossoms, and the effect of their spread on fire blight, were investigated in an orchard block of 10 rows containing 4 trees per row. Center rows of trees were sprayed with a mixture of P. fluorescens A506 and E. herbicola C9-1S at 30, 15, and 50% bloom in 1994, 1995, and 1996, respectively. Immediately after spraying, antagonists were detected only on treated blossoms. In 1994 and 1996, as bloom progressed, both P. fluorescens A506 and E. herbicola C9-1S were detected on nontreated blossoms located up to 4 rows (10 m) from the treated rows. In 1995, establishment of the antagonists on treated blossoms was poor and spread to nontreated trees was limited, apparently because of cold temperatures. Each year, honey bees were used to inoculate all trees with E. amylovora at 80% bloom. After full bloom in 1994 and 1996, the proportion of blossoms with E. amylovora populations >105 CFU per flower were highest in the outermost rows, and decreased linearly (P < 0.05) with proximity to treated rows. In 1994, diseased blossom clusters decreased significantly (P < 0.05) from the outermost rows to the treated rows, but there was no significant effect of distance on disease incidence in 1995 or 1996. Secondary colonization of blossoms by P. fluorescens A506 and E. herbicola C9-1S can play a role in disease suppression, but, among seasons, rates of secondary colonization by P. fluorescens A506 and E. herbicola C9-1S were variable, indicating that multiple applications of antagonists may be necessary to optimize biological control.

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