Evaluation of fungal isolates for the inhibition of vegetative growth of Venturis inaequalis

1997 ◽  
Vol 75 (4) ◽  
pp. 626-631 ◽  
Author(s):  
A. Ouimet ◽  
O. Carisse ◽  
P. Neumann
Keyword(s):  
Biological Control ◽  
Vegetative Growth ◽  
Biological Control Agent ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Inhibitory Effect ◽  
Control Agent ◽  
Dual Culture ◽  
Inhibitory Effects ◽  
Aureobasidium Sp

As a part of a broader study on biological control of apple scab, caused by Venturia inaequalis, a collection of 183 microorganisms originating from apple leaf litter was evaluated for their inhibitory effects on the vegetative growth of V. inaequalis. In a first screening, based on dual culture, 31 isolates (17%) showed inhibition. From these isolates, 11 fungi were selected for quantitative evaluation based on the presence of a distinct zone of inhibition. The selected fungi were evaluated again, in a more precise test, which indicated that isolates P164A (Ophiostoma sp.), P66A (Chaetophoma sp.), P26A (Aureobasidium sp.), P59A (Phoma sp.), and P28A (unidentified) inhibited 95.3, 88.9, 85.8, 80.7, and 80.1% of mycelial growth, respectively. Inhibition by the most effective fungus (Ophiostoma sp.) lasted for more than 58 days. A test using culture filtrates, incubated over time, was carried out to determine whether the living fungus was a prerequisite for inhibition. The inhibitory effect of metabolites secreted by the selected fungi was less than 5%. This study revealed the potential of at least five fungi that could be considered in the development of a biological control agent against V. inaequalis. Key words: antifungal inhibition, apple scab, biological control.

scholarly journals Effect of Timing of Application of the Biological Control Agent Microsphaeropsis ochracea on the Production and Ejection Pattern of Ascospores by Venturia inaequalis

2004 ◽  
Vol 94 (12) ◽  
pp. 1305-1314 ◽  
Author(s):  
O. Carisse ◽  
D. Rolland
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Control Agent ◽  
Sterile Leaf ◽  
Ascospore Production ◽  
Fall Application ◽  
Leaf Disks

Field and in vitro trials were conducted to establish the influence of the biological control agent Microsphaeropsis ochracea on the ejection pattern of ascospores by Venturia inaequalis and on apple scab development, and to establish the best timing of application. The ejection pattern of ascospores was similar on leaves sprayed with M. ochracea and on untreated leaves. Fall application of M. ochracea combined with a delayed-fungicide program was evaluated in orchards with intermediate and high scab risk. For both orchards, it was possible to delay the first three and two infection periods in 1998 and 1999, respectively, without causing significant increase or unacceptable leaf and fruit scab incidence. To evaluate the best timing of application, sterile leaf disks were inoculated with V. inaequalis and then with M. ochracea 0, 2, 4, 6, 8, 10, 12, 14, and 16 weeks later. After incubation under optimal conditions for pseudothecia development, the number of ascospores was counted. Similarly, M. ochracea was sprayed on scabbed leaves on seven occasions from August to November 1999 and 2000. Leaves were overwintered on the orchard floor and ascospore production was evaluated the following spring. Ascospore production was reduced by 97 to 100% on leaf disks inoculated with M. ochracea less than 6 weeks after inoculation with V. inaequalis, but ascospore production increased with increasing period of time when M. ochracea was applied 8 to 16 weeks after the inoculation with V. inaequalis. In the orchard, the greatest reduction in production of ascospores (94 to 96% in 2000 and 99% in 2001) occurred on leaves sprayed with M. ochracea in August. The production of ascospores was reduced by 61 to 84% in 2000 and 93% in 2001 on leaves sprayed with M. ochracea in September, reduced by 64 to 86% in 2000 and 74 to 89% in 2001 on leaves sprayed in October, and reduced by 54 and 67% in 2000 and 2001, respectively, on leaves sprayed in November. It was concluded that M. ochracea should be applied in August or September and that ascospore maturation models and delayed-fungicide program could be used in orchards treated with this biological control agent.

scholarly journals Biological Control of Crown Gall of Grapevine, Rose, and Tomato by Nonpathogenic Agrobacterium vitis Strain VAR03-1

2008 ◽  
Vol 98 (11) ◽  
pp. 1218-1225 ◽  
Author(s):  
A. Kawaguchi ◽  
K. Inoue ◽  
Y. Ichinose
Keyword(s):  
Biological Control ◽  
Crown Gall ◽  
Biological Control Agent ◽  
Inhibitory Effect ◽  
Control Agent ◽  
Inhibitory Effects ◽  
Agrobacterium Vitis ◽  
Colony Forming Units ◽  
Nonpathogenic Strain ◽  
A Cell

A nonpathogenic strain of Agrobacterium vitis VAR03-1 was tested as a biological control agent for crown gall of grapevine (Vitis vinifera). When roots of grapevine, rose (Rose multiflora), and tomato (Lycopersicon esculentum) were soaked in a cell suspension of antagonists before planting in soil infested with tumorigenic A. vitis, A. rhizogenes, and A. tumefaciens, respectively, treatment with VAR03-1 significantly reduced the number of plants with tumors and disease severity in the three plant species. The inhibitory effects of treatment with VAR03-1 and the nonpathogenic A. rhizogenes strain K84 on crown gall of rose and tomato were almost identical, and the inhibitory effect of VAR03-1 on grapevine was superior to that of K84. Moreover, VAR03-1 greatly controlled crown gall of grapevine due to tumorigenic A. vitis in the field. VAR03-1 established populations averaging 106 colony forming units (CFU)/g of root in the rhizosphere of grapevine and persisted on roots for 2 years. VAR03-1 was bacteriocinogenic, producing a halo of inhibition against those three species of Agrobacterium. This is the first report that a nonpathogenic strain, VAR03-1, can effectively control crown gall caused by tumorigenic A. vitis, A. rhizogenes, and A. tumefaciens.

scholarly journals Cladobotryum mycophilum as Potential Biocontrol Agent

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 891
Author(s):  
Mila Santos ◽  
Fernando Diánez ◽  
Alejandro Moreno-Gavíra ◽  
Brenda Sánchez-Montesinos ◽  
Francisco J. Gea
Keyword(s):  
Biological Control ◽  
Fusarium Oxysporum ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Control Agent ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Potential Biocontrol Agent

A study was conducted to explore the efficacy of potential biocontrol agent Cladobotryum mycophilum against different phytopathogenic fungi. The growth rates of 24 isolates of C. mycophilum were determined, and their antagonistic activity was analysed in vitro and in vivo against Botrytis cinerea, Fusarium oxysporum f. sp. radicis-lycopersici, Fusarium oxysporum f.sp. cucumerinum, Fusarium solani, Phytophthora parasitica, Phytophthora capsici, Pythium aphanidermatum and Mycosphaerella melonis. Most isolates grow rapidly, reaching the opposite end of the Petri dish within 72–96 h. Under dual-culture assays, C. mycophilum showed antagonistic activity in vitro against all phytopathogenic fungi tested, with mycelial growth inhibition ranging from 30 to 90% against all the different phytopathogens tested. Similarly, of all the selected isolates, CL60A, CL17A and CL18A significantly (p < 0.05) reduced the disease incidence and severity in the plant assays compared to the controls for the different pathosystems studied. Based on these results, we conclude that C. mycophilum can be considered as a potential biological control agent in agriculture. This is the first study of Cladobotryum mycophilum as a biological control agent for different diseases caused by highly relevant phytopathogens in horticulture.

Effect of Bactericine as a Treatment for the Control of Listeria monocytogenes in Refrigerated Meat Products

2013 ◽  
Vol 781-784 ◽  
pp. 1322-1327
Author(s):  
Li Juan Yu ◽  
Li Liu ◽  
Hong Xing Zhang ◽  
Yuan Hong Xie ◽  
Hui Liu ◽  
...  
Keyword(s):  
Biological Control ◽  
Listeria Monocytogenes ◽  
Antimicrobial Agent ◽  
Growth Inhibition ◽  
Biological Control Agent ◽  
Meat Products ◽  
Bactericidal Effect ◽  
Inhibitory Effect ◽  
Control Agent ◽  
Control Samples

The aim of this research was to investigate the inhibitory effect of bacteriocin for use as a biological control agent against Listeria monocytogenes in refrigerated meat products. And this bacteriocin was evaluated for their effectiveness as a preservative on pork. The bacteriocin-treated pork was compared with a control pork sample regarding the number of listeria colony count. After 10 days of storage at 4 °C, the population of Listeria monocytogenes was increased from 5.7×105 to 3.7×108 CFU/mL in control samples. In test samples, the population of Listeria monocytogenes underwent a slight increased from 5.7×103 to 6.0×105 CFU/mL. During 10 days of storage, the percentage of growth inhibition ranged from 82.6% to 99.8%, bacteriocin showed their inhibitory effect on Listeria monocytogenes. These results indicated that the studied bacteriocin exhibited bactericidal effect against Listeria monocytogenes strain at refrigerated temperatures, and bacteriocin could be used as antimicrobial agent to preserve the shelf life of refrigerated meat products.

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 Uji Antagonisme Bacillus cereus terhadap Rhizoctonia solani dan Sclerotium rolfsii

2016 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Nurul Hidayah ◽  
Titiek Yulianti
Keyword(s):  
Biological Control ◽  
Growth Rate ◽  
Rhizoctonia Solani ◽  
Biological Control Agent ◽  
Sclerotium Rolfsii ◽  
Control Agent ◽  
Dual Culture ◽  
Bacillus Sp ◽  
Unfavorable Condition

<p>Jamur Rhizoctonia solani dan Sclerotium rolfsii merupakan kelompok jamur steril (tidak menghasilkan spora) tetapi dapat menghasilkan sklerosia sebagai sumber inokulum primer, dan struktur istirahat jamur yang dapat bertahan selama beberapa tahun di dalam tanah saat kondisi lingkungan kurang menguntungkan. Penggunaan fungisida, fumigasi, dan solarisasi tanah telah digunakan untuk mengendalikan kedua jamur tersebut, namun hasil yang diperoleh masih beragam. Pengendalian hayati dengan menggunakan bakteri Bacillus sp. yang merupakan salah satu kelompok agens hayati patogen diketahui memberikan hasil yang baik pada beberapa tanaman. Penelitian yang bertujuan menguji potensi B. cereus dalam menghambat pertumbuhan jamur R. solani dan S. rolfsii secara in vitro dilaksanakan di Laboratorium Fitopatologi Balittas dengan menggunakan metode dual culture pada media potato dextrose agar (PDA). Miselia jamur R. solani dan S. rolfsii masing-masing berumur 5 hari diambil dengan menggunakan cork borer ukuran 0,5 cm ditanam pada media PDA berhadapan dengan B. cereus dengan jarak 3 cm. Penelitian disusun dalam rancangan acak lengkap dan diulang empat kali. Pengamatan dilakukan terhadap persentase penghambatan pertumbuhan jamur oleh Bacillus sp. dan laju pertumbuhan jamur. Hasil penelitian menunjukkan bahwa Bacillus sp. mampu menghambat pertumbuhan miselia R. solani dan S. rolfsii masing-masing sebesar 68,9% dan 33% pada hari ketiga setelah perlakuan. Keberadaan B. cereus dapat memperlambat laju pertumbuhan R. solani (15,5 mm/24 jam), dibandingkan perlakuan kontrol (tanpa B. cereus) sebesar 19,7 mm/24 jam. Hasil ini menunjukkan bahwa B. cereus dapat menghambat pertumbuhan R. solani dan berpotensi untuk dikembangkan sebagai agens hayati.</p><p> </p><p>Rhizoctonia solani and Sclerotium rolfsii (the causal agents of damping off disease on various hosts) are the group of sterile fungi that cannot produce spores. Nevertheless, they produce sclerotia as primary inocula and resting spores when facing unfavorable condition. Several control methods using chemical fungicides and solarization had been conducted, but the results were still inconsistent. In addition, the use of Bacillus sp. as a biological control agent for several plant diseases had provided successful results. Furthermore, the research aimed to evaluate the potency of B. cereus towards R. solani and S. rolfsii in vitro was carried out in the laboratory of phytopathology using dual culture method on PDA medium. Five days of R. solani and S. rolfsii miselia were plugged and inoculated on PDA medium toward B. cereus. The research was arranged by completely randomized design with four replicates. The percentage of fungal inhibition and fungal growth rate were observed. The result showed that B. cereus exhibited mycelial growth inhibition activity of R. solani and S. rolfsii by 68,9% and 33% three days after treatments, respectively. The result also indicated that<br />B. cereus has a potential prospect to be developed as a biological control agent because the bacteria could suspend the growth rate of R. solani.</p>

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