scholarly journals Effect of Pathogen Aggressiveness and Vinclozolin on Efficacy of Rhodotorula glutinis PM4 Against Botrytis cinerea on Geranium Leaf Disks and Seedlings

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1262-1268 ◽  
Author(s):  
J. W. Buck ◽  
S. N. Jeffers
Keyword(s):  
Botrytis Cinerea ◽  
Biological Control Agent ◽  
Rhodotorula Glutinis ◽  
Control Agent ◽  
Lesion Development ◽  
Biocontrol Efficacy ◽  
Lesion Diameter ◽  
Reduced Rate ◽  
Leaf Disks

Efficacy of the yeast Rhodotorula glutinis isolate PM4 as a biological control agent against 29 isolates of Botrytis cinerea obtained from greenhouse-grown ornamentals was assessed in vitro on geranium leaf disks. Isolates of B. cinerea varied in aggressiveness in the absence of either biological or chemical controls; diameters of lesions produced on leaf disks ranged from 0.8 to 12.3 mm. Efficacy of R. glutinis PM4 against the different isolates of B. cinerea varied greatly; lesion diameters ranged from 0.2 to 10.3 mm when the yeast was present. The yeast significantly reduced lesion development by 16 B. cinerea isolates in each of two replicate trials and by 9 isolates in one of the trials; however, 3 isolates were not inhibited by the yeast on geranium leaf disks. The yeast significantly reduced lesion development by B. cinerea isolate 01, used as a standard for comparison, in four of six trials. Fourteen of the B. cinerea isolates were inoculated onto geranium seedlings and produced a range of lesion sizes (2.9 to 16.4 mm), similar to that produced on leaf disks. Efficacy of the yeast in combination with a reduced rate (0.1×) of the fungicide vinclozolin (50 μg of active ingredient ml-1) was evaluated on geranium seedlings against 10 isolates of B. cinerea that were resistant to vinclozolin. Addition of vinclozolin to the yeast significantly reduced lesion diameter by five of the isolates compared with diameters of lesions produced in the presence of the yeast alone. Lesions produced by nine of the resistant isolates were 2.6 mm or smaller in both trials on plants treated with the mixture of yeast and vinclozolin. The effect of vinclozolin concentration (0 to 500 μg a.i. ml-1) on biocontrol efficacy of R. glutinis PM4 was evaluated using three resistant isolates of B. cinerea and geranium seedlings. Disease control was significantly better at higher concentrations of fungicide for two of the isolates. Linear regression of lesion diameter against vinclozolin concentration showed a significant effect on yeast biocontrol efficacy with B. cinerea isolate FL-2-b (y = 6.20 – 0.63x; r2= 0.74) and isolate BR-1 (y = 4.10 – 0.32x; r2 =0.28) but there was no significant effect with isolate GG-2-b. Overall, PM4 exhibited biocontrol activity on both geranium leaf disks and seedlings against a number of isolates of B. cinerea that varied in aggressiveness. Variability in biocontrol efficacy against isolates resistant to vinclozolin usually was reduced by the addition of vinclozolin.

scholarly journals Combinations of Fungicides with Phylloplane Yeasts for Improved Control of Botrytis cinerea on Geranium Seedlings

2004 ◽  
Vol 94 (2) ◽  
pp. 196-202 ◽  
Author(s):  
J. W. Buck
Keyword(s):  
Disease Control ◽  
Botrytis Cinerea ◽  
Ornamental Plants ◽  
Rhodotorula Glutinis ◽  
Lesion Development ◽  
Biocontrol Efficacy ◽  
Highly Effective ◽  
Cell Densities ◽  
Phylloplane Yeasts

Control of Botrytis cinerea on geranium seedlings was evaluated in treatments with phylloplane yeasts in combination with 10 fungicides used to manage Botrytis blight of ornamental plants. Rhodotorula glutinis PM4 significantly reduced the development of lesions caused by B. cinerea on geranium cotyledons; however, yeast biocontrol efficacy was highly variable between trials. Treatment with the yeast in combination with azoxystrobin or trifloxystrobin at one tenth the labeled rate (7.5 μg a.i. ml-1) or the full labeled rate (7.5 μg a.i. ml-1) reduced lesion development, compared to treatment with the yeast or the fungicide alone. Vinclozolin at half the labeled rate or the full labeled rate (250 or 500 μg a.i. ml-1), in combination with R. glutinis PM4, significantly reduced the development of lesions caused by an isolate of B. cinerea resistant to vinclozolin. Copper hydroxide and iprodione at one-tenth the labeled rates, with or without yeast, were highly effective in limiting lesion development. Mancozeb did not increase the biocontrol efficacy of the yeast, and thiophanate-methyl negatively affected the yeast efficacy. Improved disease control was observed in treatments with vinclozolin at the labeled rate and R. glutinis PM4 at cell densities of 5 × 105 and 1 × 106 cells ml-1, but not 1 × 105 cells ml-1, on seedlings co-inoculated with B. cinerea in a suspension containing 1 × 105 conidia ml-1. Disease control improved in treatments with combinations of vinclozolin and eight other isolates of R. glutinis, two isolates of R. graminis, and two isolates of R. mucilaginosa. Biocontrol was not observed in treatments with two isolates of R. minuta. The combination of yeast and vinclozolin significantly reduced the germination of conidia of B. cinerea and the growth of R. glutinis PM4 in vitro. All combinations of R. glutinis PM4 with azoxystrobin, trifloxystrobin, or vinclozolin provided highly effective and consistent disease control not observed in treatments with the fungicides alone or the yeast alone.

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.

In vitro antagonism of Botrytis cinerea by phylloplane yeasts

2002 ◽  
Vol 80 (8) ◽  
pp. 885-891 ◽  
Author(s):  
James W Buck
Keyword(s):  
Botrytis Cinerea ◽  
Rhodosporidium Toruloides ◽  
Yeast Cells ◽  
Lesion Development ◽  
Nitrogen Base ◽  
Wide Range ◽  
Biocontrol Activity ◽  
Phylloplane Yeasts ◽  
Leaf Disks

The influence of inoculum and nutrient concentrations on the in vitro antagonism of Botrytis cinerea by phylloplane yeasts was investigated with detached leaf disk and conidial germination assays. Rhodosporidium toruloides Y-1091 significantly reduced lesion development after 96 h on geranium leaf disks when co-inoculated at 1 × 106 or 1 × 107 yeast cells/mL with B. cinerea conidia at 1 × 104 or 1 × 105 conidia/mL. No effect on lesion development was observed when yeast and fungus were co-inoculated at a 1:1 ratio. Biocontrol activity of R. toruloides was greatest in 20 mM glucose and 20-fold dilute yeast nitrogen base. Twenty-five phylloplane yeasts exhibited a wide range of biocontrol activity when screened for antagonism of B. cinerea on geranium leaf disks (1 × 106 yeast cells/mL, 1 × 105 conidia/mL). Lesion development was significantly reduced by yeasts initially identified as poor antagonists when inoculated at higher concentrations (5 × 106 or 1 × 107 yeast cells/mL) with B. cinerea. Both poor and good antagonists significantly reduced in vitro germination of B. cinerea conidia. The presence of B. cinerea conidia had a greater effect on the growth of two poor antagonists compared with two good antagonists on leaf disks. These data suggest that many phylloplane yeasts will antagonize B. cinerea under conditions of low nutrient availability and with high antagonist to pathogen ratios.Key words: yeast, biological control, competition, nutrients, germination, Rhodosporidium toruloides.

The potential biocontrol agent Paenibacillus polymyxa TP3 produces fusaricidin-type compounds involved in the antagonism against gray mold pathogen Botrytis cinerea

2021 ◽  
Author(s):  
Shuen-Huang Tsai ◽  
Yu-Ting Chen ◽  
Yu-Liang Yang ◽  
Bo-Yi Lee ◽  
Chien-Jui Huang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Botrytis Cinerea ◽  
Biological Control Agent ◽  
Imaging Mass Spectrometry ◽  
Paenibacillus Polymyxa ◽  
Field Trials ◽  
Gray Mold ◽  
Control Agent ◽  
Antagonistic Activity ◽  
New Variant

Paenibacillus polymyxa is a beneficial bacterium for plant health. Paenibacillus polymyxa TP3 exhibits antagonistic activity toward Botrytis cinerea and alleviates gray mold symptoms on the leaves of strawberry plants. Moreover, suppression of gray mold on the flowers and fruits of strawberry plants in field trials, including vegetative cells and endospores, was demonstrated, indicating the potential of strain TP3 as a biological control agent. To examine the anti-B. cinerea compounds produced by P. polymyxa TP3, matrix‐assisted laser‐desorption/ionization time‐of‐flight mass spectrometry was performed and fusaricidin-corresponding mass spectra were detected. Moreover, fusaricidin-related signals appeared in imaging mass spectrometry of TP3 when confronted with B. cinerea. By using liquid chromatography-mass spectrometry-based molecular networking approach, several fusaricidins were identified including a new variant of m/z 917.5455 with serine in the first position of the hexapeptide. Via advanced mass spectrometry and network analysis, fusaricidin-type compounds produced by P. polymyxa TP3 were efficiently disclosed and were presumed to play roles in the antagonism against gray mold pathogen B. cinerea.

scholarly journals Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
M. E. Ali ◽  
A. A. Khan ◽  
A. M. Akanda ◽  
Md. Kamal Uddin ◽  
...  
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Control Agent ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Antagonistic Bacteria ◽  
And Storage

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacteriumErwinia carotovorasubsp.carotovora(Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was testedin vitroagainst the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited thein vitrogrowth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genusBacillusand the isolate E-45 asLactobacillussp. The stronger antagonistic activity against Ecc P-138 was found in E-65in vitroscreening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

scholarly journals Assessment of the Importance of Similarity in Carbon Source Utilization Profiles between the Biological Control Agent and the Pathogen in Biological Control of Bacterial Speck of Tomato

2002 ◽  
Vol 68 (9) ◽  
pp. 4383-4389 ◽  
Author(s):  
Pingsheng Ji ◽  
Mark Wilson
Keyword(s):  
Biological Control ◽  
Carbon Source ◽  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Biological Control Agent ◽  
Carbon Sources ◽  
Control Agent ◽  
Carbon Source Utilization ◽  
Bacterial Speck

ABSTRACT Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, was used to determine whether similarity in carbon source utilization between a preemptive biological control agent and the pathogen was significant in determining the ability of the bacterium to suppress disease. Similarity in carbon source utilization was quantified as the ratio of the number of tomato carbon sources utilized in vitro by the biological control agent to the number of tomato carbon sources utilized in vitro by the target pathogen (the niche overlap index [NOI]). Suppression of the disease was quantified as the percent reduction in disease severity compared to the pathogen-only control when nonpathogenic bacteria were applied to foliage 48 h prior to the pathogen. In the collection of 36 nonpathogenic bacterial strains, there was a significant (P < 0.01), but weak (r2 = 0.25), correlation between reduction in disease severity and similarity in carbon source utilization, suggesting that similarity in carbon source use was significant in determining ability to suppress disease. The relationship was investigated further using catabolic mutants of P. syringae strain TLP2, an effective biological control agent of speck. Catabolic mutants exhibited lower levels of similarity (NOI = 0.07 to 0.90) than did wild-type TLP2 (NOI = 0.93). With these catabolic mutants there was a significant (P < 0.01), and stronger (r2 = 0.42), correlation between reduction in disease severity and similarity in carbon source utilization. This suggests that similarity in carbon source utilization was a more important component of biological control ability for the catabolic mutants than for the nonpathogenic bacteria. Together, these studies indicate that suppression of bacterial speck of tomato was correlated with nutritional similarity between the pathogenic and nonpathogenic bacteria and suggest that preemptive utilization of carbon sources was probably involved in the biological control of the disease by both the naturally occurring nonpathogenic bacteria and the catabolic mutants.

Catenaria anguillulae as an efficient biological control agent of Anguina tritici in vitro

2012 ◽  
Vol 61 (3) ◽  
pp. 185-193 ◽  
Author(s):  
K.P. Singh ◽  
S.S. Vaish ◽  
Niranjan Kumar ◽  
K.D. Singh ◽  
Minakshi Kumari
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Control Agent ◽  
Catenaria Anguillulae

scholarly journals YEASTS INHIBIT DEVELOPMENT OF LESIONS IN `GOLDEN DELICIOUS' APPLES INOCULATED WITH BOTRYTIS CINEREA

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 754e-754
Author(s):  
Jeff Anderson ◽  
Alexander B. Filonow ◽  
Helen S. Vishniac
Keyword(s):  
Biological Control ◽  
Botrytis Cinerea ◽  
Lesion Development ◽  
Partial Control ◽  
Low Temperature Storage ◽  
Lesion Diameter ◽  
Golden Delicious ◽  
Sporobolomyces Roseus ◽  
Paper Towels ◽  
Temperature Storage

Strategies to reduce postharvest losses of fruit to pathogens include low-temperature storage, fungicides, and use of organisms with biological control capabilities. Our objective was to determine the effectiveness of two yeast isolates in inhibiting lesion development caused by Botrytis cinerea (Bc) on freshly harvested apples of different maturity. `Golden Delicious' apples were harvested on 29 Aug., 23 Sept., and 10 Oct. 1995. Apples comprising the seven treatments [control, wound, Cryptococcus humicola (Ch), Sporobolomyces roseus (Sr), Bc, Bc + Ch, Bc + Sr] were placed in plastic boxes with damp paper towels. Each day for 7 days, ethylene and CO2 production and lesion diameter at the wound were recorded. Ethylene and CO2 production were not affected by treatment. Lesion diameter on apples treated with Bc was smaller on the first harvest, compared with the second and third harvests. Sr provided partial control on the second and third harvests, and Ch completely inhibited lesion development on all harvests.

scholarly journals Potensi Cendawan Endofit sebagai Pengendali Hayati Penyakit Busuk Pangkal Batang (Phytophthora capsici) pada Bibit Cabai

2018 ◽  
Vol 13 (5) ◽  
pp. 161
Author(s):  
Evan Purnama Ramdan ◽  
Efi Toding Tondok ◽  
Suryo Wiyono ◽  
Sri Hendrastuti Hidayat ◽  
Widodo Widodo
Keyword(s):  
Endophytic Fungi ◽  
Biological Control Agent ◽  
Phytophthora Capsici ◽  
Control Agent ◽  
Stem Rot ◽  
Rot Disease ◽  
Important Disease ◽  
Penicillium Strain

Stem rot disease caused by Phytophthora capsici is an important disease on chilli. Eight endophytic fungi that had been isolated and screened based on pathogenecity test were further tested for their potential as the biological control agent of the stem rot disease of chilli. The endophytic fungi suspension was applied twice during the trial. The first application was on 100 seed lot, by soaking them in 100 mL of suspension. The second application was on the 3 weeks-old chili seedlings by drenching them with 10 mL suspension per plant. The concentration of endophytic fungi  in the suspension was 2.8 × 106 cfu mL-1. The disease intensity and AUDPC value were measured for 4 weeks after the pathogen inoculation. The growth inhibition test of P. capsici  was performed in vitro and the colonization abilities of endophytic fungi were observed at 4 weeks-old chilli seedlings. Eight endophytic fungi  inhibited the growth of the P. capsici, and two of those isolates namely Penicillium strain MAG1 and Penicillium strain PAB2 showed antibiosis mechanism. Endophytic fungi has the ability more to colonize at the root (26–60%) than in the stem (20–40%). Fusarium strain MAGR1 has the highest level of endophytic colonization i.e. 60% compared to others.  Based on in vivo assay, six endophytic fungi isolates, i.e. Fusarium strain MAGR1, Penicillium strain MAG1, Penicillium strain PAB2, sterile hyphae HAJ1, sterile hyphae HAJ2, and  sterile hyphae PBG7, showed the potency to control stem rot disease with inhibition level of 25.5–35.5%

Sign in / Sign up

Export Citation Format

Share Document