scholarly journals Isolation and evaluation of biocontrol agents in controlling anthracnose disease of mango in Thailand

2016 ◽  
Vol 56 (3) ◽  
pp. 306-311 ◽  
Author(s):  
Nattawut Rungjindamai

Abstract The agricultural based economy is a core business in Thailand and food export is one of the main sources of income for the Thai population. However, pesticides are overused and misused. As a result there is an urgent need to reduce the use of synthetic chemicals. Biological control offers an alternative to the use of pesticides. Mango (Mangifera indica L.) is widely planted in Thailand and is one of the major cash crops for international export. However, mango suffers from various diseases especially anthracnose, a fungal disease caused by Colletotrichum gloeosporioides. One hundred and twelve isolates of epiphytic microbes were isolated from healthy leaves and fruits of mangoes; this included 93 and 19 isolates of epiphytic bacteria and yeasts, respectively. They were screened for bioactivity against a pathogenic strain of C. gloeosporioides isolated from diseased mangoes using a dual culture technique. Out of 112 isolates, eight isolates exhibited at least 60% inhibition. These isolates were further screened for their inhibition on mango using fruit inoculation. Two isolates reduced the lesion sizes caused by C. gloeosporioides compared to control treatment. These two isolates, based on phenotypical and biochemical tests, were identified as Bacillus sp. MB61 and Bacillus sp. LB72.

2019 ◽  
Vol 32 ◽  
pp. 207-219
Author(s):  
Mohammad A. Jaber ◽  
Mohammed A. Fayyadh

Thirty-nine isolates of Actinomycetes were isolated from different sources such as rhizosphere and plant roots of Alfalfa, Clovers, cowpea, Mung bean, sorghum and date palms. Biochemical tests showed that all isolates were gram positive and capable of producing amylase, catalase and gelatinase enzymes. The isolates showed a positive test for gram staining. The isolates were capable of producing the enzymes of amylase, catalase and gelatinase. Dual culture technique showed that Streptomyces griseorubens, S. tendae 6, S. tendae2, S. tendae 5, S. parvulus and S. tendae 6 had high antagonistic activity against Macrophomina phaseolina as a zone of inhibition reached 15, 14, 13, 15, 14 and 12mm, respectively. Molecular identification revealed that actinomycetes isolate No 15, 23, 24 and 30 isolated from rhizosphere of Clovers, Sorghum, Alfalfa, Mung bean had 99% similarity with S. tendae while Actinomycetes No 38 isolated from rhizosphere of Cowpea had 99% similarity with S. grseorubens .and isolate No 27 isolated from date palms had 99% similarity with S.parvulus. all isolate were deposited at NCBI with GenBank accession number LC499602.1, LC499603.1, LC499606.1, LC499607.1, LC499604.1, LC499605.1. The isolate of S. griseorubens showed high efficacy in reducing disease. Which was 10.1% compared with 49.5% in control treatment on cowpea. 22.0% in mung bean compared to 43.4% in control treatment. In the field experiment, the results showed that soil treated with Actinomycetes isolates led to an increase in the percentage of seed germination and reduced the percentage of fungus infection. S. griseorubens reduced the percentage of infection to 11.54% compared to 32.33% in control treatment.


2018 ◽  
Vol 31 (2) ◽  
pp. 11-23
Author(s):  
Lina K. Awad ◽  
Mohammed A. Fayyadh

A 28 Actinomycetes isolates which collected from different environmental sources in Basra province were described as Gram positive and are characterized by producing branching hyphae. Two isolates were identified by molecular analysis of 16 S r RNA gene. Molecular identification confirmed that two isolates of Actinomycetes from soil had a similarity of 99% with Streptomyces griseus. The sequence has been deposited at NCBI with Gen bank accession number (NBRC 14886, AB 184627. 1). While the isolates of date palm roots was analogous to Brevibacterium celere and the sequence of this strain deposited at NCBI with Gen bank accession number (DQ164,K414744601). The dual culture technique showed that Actinomyces isolates 44 had high antagonistic activity against Rhizoctonia solani as inhibition zone reached 1.7 cm, in contrast to Actinomyces 24 and S. griseus which revealed a high antagonistic activity against Pythium sp. with inhibition zone reached 1.2 cm for both isolates. Pots experiment showed all Actinomyces isolates were significantly reduced cucumber seedling damping off caused by R. solani and Pythium sp. the disease incidence for R. solani damping off were reduced to 1.0% in actinomycetes 44, Actinomycetes 24 and B. celere treatment compared to 11.37 % in control treatment. Disease incidence at Pythium sp. damping off was reduced to 1.0% in Actinomycetes isolates compared with that in control treatment (4.33%). According to this study there is possibility for isolating Actinomycetes isolates which isolated from different environments sources have the ability for reducing cucumber damping off disease caused by R. solani and Pythium sp.


2016 ◽  
Vol 1 (02) ◽  
pp. 138-144
Author(s):  
Rashmi Nigam ◽  
A. K. Sharma ◽  
Joginder Singh

Plant growth promoting rhizobacteria (PGPR) are a heterogeneous group of bacteria that are found in the rhizosphere and rhizoplane which can improve plant growth. Pseudomonas spp. is one of the most promising groups of PGPR which can control plant pathogenic microbes in the soil. In this study, an attempt was made to isolate Pseudomonas spp., a potent PGPR in the rhizosphere. Through appropriate microbiological and biochemical methods, the study demonstrated the presence of fluorescent and nonfluorescent Pseudomonads in the rhizosphere of pea. 12 different strains of Pseudomonas were isolated from pea rhizosphere and identified by biochemical tests. Out of these strains five were screened against wilt and root rot pathogens of pea. Antagonistic activity of Pseudomonas isolates were evaluated against wilt and root rots pathogens i.e. Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum through dual culture technique. The study exhibited that all Pseudomonas strains significantly inhibited the growth of Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum as compared to control. Among all the Pseudomonas isolates Ps5 showed maximum inhibition against Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum. Augmentation of such PGPR will ensure a healthy micro climate for pea.


2013 ◽  
Vol 25 (2) ◽  
pp. 123-132 ◽  
Author(s):  
Aleksandra Bogumił ◽  
Lidia Sas Paszt ◽  
Anna Lisek ◽  
Paweł Trzciński ◽  
Anton Harbuzov

ABSTRACT The antagonistic activity of 52 isolates of Trichoderma spp. against Botrytis cinerea was tested in in vitro conditions using the dual culture technique. The results revealed that all of the Trichoderma isolates had the ability to inhibit the mycelial growth of grey mould. The percentage reduction in the growth of Botrytis cinerea after six days of incubation at 25ºC varied between 45-78%. The isolates Tr43 and Tr52 showed the highest antagonistic activity (Tr43 - 76%; Tr52 - 78%). Biochemical and molecular identification indicated that both isolates were T. atroviride. The isolates showed differences in the utilisation of 11 to 96 different carbon sources. Additional biochemical tests revealed the ability of Tr43 and Tr52 to produce siderophores, indole-3-acetic acid and chitinases. Neither of the isolates gave positive results regarding phosphate solubilisation on Pikovskaya’s medium.


Author(s):  
H.V. Parmar ◽  
N.M. Gohel

Background: Chickpea wilt complex caused by several soil-borne pathogens is the major yield-reducing malady worldwide. Biological control is one of the best, low-cost and ecologically sustainable method for managing plant diseases caused by soil-borne pathogens. Methods: In this present investigation Panchagavya and Trichoderma spp. were evaluated by following poisoned food technique and dual culture technique against wilt complex causing pathogens i.e. Fusarium oxysporum f. sp. ciceri, Fusarium solani and Macrophomina phaseolina. Result: Among the different isolates of Trichoderma spp. evaluated, Trichoderma viride (AAU isolate) was highly antagonistic to F. oxysporum f. sp. ciceri (52.78%) and F. solani (65.37%) whereas, Trichoderma asperellum (AAU isolate) was highly antagonistic to M. phaseolina (65.93%). Panchagavya at the highest concentration (50%) showed significantly higher efficacy (80.74, 66.62 and 49.67%) in inhibiting the mycelial growth of all three pathogens and at the lowest concentration it was moderately effective.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
E. K. Wanjiku ◽  
J. W. Waceke ◽  
J. N. Mbaka

Demand for organic avocado fruits, together with stringent food safety standards in the global market, has made producers to use alternative, safe, and consumer-friendly strategies of controlling the postharvest fungal disease of avocado fruits. This study assessed the in vitro efficacy of Trichoderma spp. (T. atroviride, T. virens, T. asperellum, and T. harzianum) against isolated avocado stem-end rot (SER) fungal pathogens (Lasiodiplodia theobromae, Neofusicoccum parvum, Nectria pseudotrichia, and Fusarium solani) using a dual culture technique. The Trichoderma spp. were also evaluated singly on postharvest “Hass” avocado fruits. Spore suspension at 5 × 104 conidial/ml of the Trichoderma spp. was applied on the avocado fruits at three time points, twenty-four hours before the fungal pathogen (preinoculation), at the same time as the fungal pathogen (concurrent inoculation), and 24 hours after the fungal pathogen (postinoculation). In the in vitro study, T. atroviride showed the highest mycelial growth inhibition against N. parvum (48%), N. pseudotrichia (55%), and F. solani (32.95%), while T. harzianum had the highest mycelial growth inhibition against L. theobromae. Trichoderma asperellum was the least effective in inhibiting the mycelial growth of all the pathogens. Similarly, T. virens showed the highest mycelial growth inhibition against N. pseudotrichia at 45% inhibition. On postharvest “Hass” fruits, T. atroviride showed the highest efficacy against N. parvum, N. pseudotrichia, and F. solani in all the applications. Trichoderma virens and T. harzianum were most effective against all the pathogens during postinoculation, while Lasiodiplodia theobromae was best controlled by T. virens, T. harzianum, and T. asperellum during postinoculation. Both T. atroviride and T. harzianum present a potential alternative to synthetic fungicides against postharvest diseases of avocado fruits, and further tests under field conditions to be done to validate their efficacy. The possibility of using Trichoderma spp. in the management of SER on avocado fruits at a commercial level should also be explored.


2021 ◽  
Vol 13 (1) ◽  
pp. 69-80
Author(s):  
Majida Hadi Mahdi Alsaady ◽  
Hussein Ali Salim ◽  
Rakib A. Al-ani ◽  
Hadi M. Aboud ◽  
Jamal Talib M Al Roubaie

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.


2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Rita Noveriza ◽  
Tricita H. Quimio

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.


2021 ◽  
Vol 12 (5) ◽  
pp. 339-347
Author(s):  
S. Ameer Basha ◽  
◽  
V. Ramya ◽  
A. Sajeli Begum ◽  
G. Raghavendra ◽  
...  

A study was made to evaluate the efficacy of Pseudomonas fluorescens strains, fungicides and non-conventional chemicals against Botryotinia ricini, causing grey mold disease in castor, under in vitro conditions. Among the 40 strains isolated from rhizosphere soil samples of different crops across the State of Telangana, India, only eight strains inhibited the growth of B. ricini under dual culture technique, of which strains Pf 21 (90.56%), Pf 23 (88.89%), Pf 34 (86.11%) and Pf 36 (84.17%) were the most effective. Among the seven chemicals (four fungicides and three non-conventional chemicals) tested for their efficacy, carbendazim followed by propiconazole had significant antagonistic effect against B. ricini. Exposure of healthy castor capsules to B. ricini and P. fluorescens for different time periods revealed that strains Pf 34 and Pf 36 were effective in completely inhibiting the growth of B. ricini and hence these two strains have been identified as effective biocontrol agents, on par with carbendazim, which offer scope for sustainable and integrated disease management of grey mold disease in castor.


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