scholarly journals Botanical Extracts as Biofungicides against Fungal Pathogens of Rice

2020 ◽  
Vol 43 (4) ◽  
Author(s):  
Mui Yun Wong ◽  
Sathyapriya Hamid ◽  
Nor Afifah Iskandar Shah ◽  
Nurul Husna Ab Razak
Keyword(s):  
Disease Management ◽  
Aqueous Extract ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Leaf Extract ◽  
Brown Spot ◽  
Crude Leaf Extract ◽  
Phaleria Macrocarpa ◽  
Botanical Extracts

Diseases such as blast, brown spot and sheath blight considerably affect the health and productivity of rice worldwide. Chemical fungicides have been routinely used in combating these diseases; however, a safe and environmental-friendly approach using bio-fungicides is desirable in disease management of food crop such as rice. Identification of botanical extracts with antifungal potentials would be instrumental in the development of bio-fungicides. In this study, the antifungal potentials of Andrographis paniculata, Backhousia citriodora, and Phaleria macrocarpa against selected rice fungal pathogens were analysed. Crude extracts obtained from leaves of these plants were diluted to 5, 10, 15, and 20% and tested against Pyricularia oryzae, Exserohilum rostratum, and Rhizoctonia solani in vitro using poisoned agar method. Percentage inhibition of diameter growth (PIDG) of each crude leaf extract against test pathogens was calculated. The aqueous extract of A. paniculata showed a significant mycelial inhibitory effect against P. oryzae at 20% concentration (PIDG 81.9%) as compared to other test concentrations and pathogens. On the contrary, the aqueous extract of B. citriodora at 15 and 20% concentrations had little influence on the mycelial growth inhibition on P. oryzae and E. rostratum with PIDG values less than 50%. In addition, P. macrocarpa methanol extracts at concentration of 10% and above significantly inhibited the mycelial growth of P. oryzae, E. rostratum, and R. solani (PIDG 100%). Phaleria macrocarpa leaf extract had been identified to give the highest efficacy against all three rice pathogens in vitro and therefore, has the potential to be developed into a bio-fungicide as a safe alternative to synthetic fungicides for disease management of rice.

scholarly journals Baseline Sensitivities of Fungal Pathogens of Fruit and Foliage of Citrus to Azoxystrobin, Pyraclostrobin, and Fenbuconazole

Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1186-1194 ◽  
Author(s):  
S. N. Mondal ◽  
Alka Bhatia ◽  
Turksen Shilts ◽  
L. W. Timmer
Keyword(s):  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Fungal Species ◽  
Brown Spot ◽  
Colletotrichum Acutatum ◽  
Fungicide Sensitivity ◽  
Fruit Drop ◽  
Coefficients Of Variation ◽  
Foliar Pathogens

The baseline sensitivities for mycelial growth of foliar fungal pathogens of citrus, Colletotrichum acutatum, Alternaria alternata, Elsinoe fawcettii, Diaporthe citri, and Mycosphaerella citri, the causal agents of postbloom fruit drop, brown spot of tangerine, citrus scab, melanose, and greasy spot, respectively, were determined in vitro for azoxystrobin, pyraclostrobin, and fenbuconazole. The effective dose to reduce growth by 50% (ED50 values) was determined for each pathogen-fungicide combination using five isolates from different citrus areas of Florida and eight fungicide concentrations. A discriminatory dose for each combination was selected near the ED50, and the range of sensitivity of 50 to 62 isolates of each fungal species was determined. The effect of salicylhydroxamic acid (SHAM) on the sensitivity of the five fungal species to azoxystrobin and pyraclostrobin was determined. Since mycelial growth of A. alternata was insensitive to azoxystrobin, the effect of that fungicide with and without SHAM on spore germination was assessed. The ED50 values for most fungal pathogens of citrus were relatively high compared with foliar pathogens of other tree crops. Values for azoxystrobin ranged from a low of 0.06 μg/ml with E. fawcettii to a high of >100 μg/ml with A. alternata. With pyraclostrobin, the values ranged from a low of 0.019 μg/ml with D. citri to a high of 0.87 μg/ml with A. alternata. With fenbuconazole, the lowest ED50 value was 0.21 μg/ml with M. citri and the highest was 1.01 μg/ml with C. acutatum, but A. alternata and D. citri were not tested. SHAM was inhibitory to all species and reduced growth of D. citri greatly. Inclusion of SHAM in the medium did not greatly affect the sensitivity of mycelial growth of these fungi to azoxystrobin or pyraclostrobin, nor did it affect the ED50 values for conidial germination of A. alternata. The coefficients of variation for the sensitivity of 50 to 62 isolates of each species to these fungi ranged from 7.3% with the pyraclostrobin-C. acutatum combination to a high of 55.0% with the fenbuconazole- M. citri combination. Discriminatory doses have been established for these pathogen- fungicide combinations that should be useful for detecting major shifts in fungicide sensitivity.

scholarly journals Control of bovine tick [Rhipicephalus (Boophilus) microplus] with Brunfelsia uniflora leaf extract

2019 ◽  
pp. 903-910
Author(s):  
Elaine Yae Yamashita Sugauara ◽  
ElisângelaYumi Sugauara ◽  
Rosangela Rumi Sugauara ◽  
Wanessa de Campos Bortolucci ◽  
Herika Line Marko de Oliveira ◽  
...  
Keyword(s):  
Ethyl Ester ◽  
Leaf Extract ◽  
Acid Ethyl Ester ◽  
Acaricidal Activity ◽  
Boophilus Microplus ◽  
Ex Situ ◽  
In Vitro Tests ◽  
Free Living ◽  
Crude Leaf Extract

Bovine tick has caused losses in livestock production profitability in Brazil. However, tick control has caused resistance of these ectoparasites against utilized acaricides. Alternative tick controls have been utilizing plants as sources of effective botanical acaricides. Brunfelsia uniflora is a Brazilian plant with antimicrobial and antioxidant activity; however, there are no reports on its acaricidal activity. Therefore, this study aimed to evaluate the chemical composition of B. uniflora leaf ethanolic extract and its efficiency to control bovine tick in vitro and free-living stage ex situ. The crude leaf extract was analyzed by gas chromatographer coupled to mass spectrometer (GC-MS) with identification of 17 compounds. The major compounds were phytol (22.96%), 9,12,15-octadecatrienoic acid, ethyl ester (Z,Z,Z) (21.18%), hexadecanoic acid, ethyl ester (12.74%) and vitamin E (8.77%). The crude extract presented acaricidal activity in vitro against ingurgitated adult females, larvae and eggs of bovine tick. The LC99.9 for larvae was 103.21 mg mL-1 in in vitro tests and was 100% efficient for ex situ larva test (free-living stage). B. uniflora leaf extract is an alternative for the control of the bovine tick cycle, mainly in the free-living stage (non-parasitic stage) under field conditions.

scholarly journals In vitro Study on Anti-salmonella Activities of Boerhaavia diffusa (L. syn) Leaf Extract

2019 ◽  
pp. 1-10
Author(s):  
Ologun, Oluwabusayo ◽  
Dada, Ebenezer Oluyemi ◽  
Ajayi, Kehinde Oluyemi
Keyword(s):  
Antibacterial Activity ◽  
Clinical Isolate ◽  
Optical Density ◽  
Aqueous Extract ◽  
Leaf Extract ◽  
Ethanol Extract ◽  
Salmonella Typhi ◽  
Boerhaavia Diffusa ◽  
Broth Dilution

Various strategies have been employed in the treatment and management of Salmonella infection however, Salmonella strains have gained resistance to antibiotics. This study was to determine in vitro anti-Salmonella activity of Boerhaavia diffusa leaf extract against clinical isolate of Salmonella typhi and Salmonella typhi ATCC 14028. The aqueous and ethanol extracts of B. diffusa were studied for their antibacterial activity against pathogenic Salmonella typhi. This study was carried out between April and September 2018. The in vitro antibacterial activity was performed by agar well diffusion method and broth dilution using spectrophotometric method and the results were expressed as the average diameter of zone of inhibition of bacterial growth around the well and optical density respectively. It was observed that aqueous extract exerted slightly higher activity than ethanolic extract as revealed by the mean diameter of zone of inhibitions at a concentration of 200 mg/ml, the aqueous extract had 35.21±0.47 mm (Salmonella typhi ATCC 14028) compared with ethanol extract 26.41±0.32 mm (clinical). However, in the broth dilution method, ethanol extract significantly (p=0.05) reduced the cell, at 48 hours, the optical density of clinical isolate of S. typhi treated at concentration of 200 mg/ml of extract was 0.47±0.02 nm while at the same concentration of extract, aqueous extract had an optical density of 0.52±0.11 nm respectively. The phytochemical assay revealed that tannin (5.18±0.02 mg/g) and quinone (8.45±0.13 mg/g) in ethanol extract was significantly (p=0.05) higher than aqueous extract while saponin (14.18±0.06 mg/g) was higher in the aqueous extract. The ethanol and aqueous extracts of leaves of B. diffusa whole plant exhibited significant antibacterial activity against both clinical and typed Salmonella typhi. Therefore, the plant extract could be used for the treatment of Salmonellosis, however, the in vivo studies is needed to ascertain the safety of the extract.

scholarly journals Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium

2015 ◽  
Vol 105 (9) ◽  
pp. 1183-1190 ◽  
Author(s):  
Mohammad Ali ◽  
Bosung Kim ◽  
Kevin D. Belfield ◽  
David Norman ◽  
Mary Brennan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Aqueous Extract ◽  
Dose Response ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Synthesis Methods ◽  
In Planta ◽  
Artemisia Absinthium ◽  
Plant Disease Management

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml−1 of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml−1) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

scholarly journals The ultrastructure changes of Haemonchus contortus exposed to bamboo leaves (Gigantochloa apus) aqueous extract under in vitro condition

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Budi Purwo Widiarso ◽  
WISNU NURCAHYO ◽  
KURNIASIH KURNIASIH ◽  
JOKO PRASTOWO
Keyword(s):  
Electron Microscopy ◽  
Aqueous Extract ◽  
Haemonchus Contortus ◽  
Leaf Extract ◽  
Structural Changes ◽  
Ultrastructural Changes ◽  
Bamboo Leaves ◽  
Transmission Electron ◽  
External Part

Abstract. Widiarso, Nurcahyo W, Kurniasih, Prastowo J. 2021. The ultrastructure changes of Haemonchus contortus exposed to bamboo leaves (Gigantochloa apus) aqueous extract under in vitro condition. Biodiversitas 22: 1-5. The ultrastructural changes induced in adult Haemonchus contortus in vitro using the aqueous extract of bamboo leaves were assessed using scanning electron microscopy (SEM). The H. contortus adult females were obtained from three groups and treatment was repeated thrice. The first group (T0) was not treated with bamboo leaves; 100% of the worms lived. The second group (T1), treated with 0.1% bamboo leaf-extract, had 50% mortality 4 h after examination. The third group (T2), treated with 1% bamboo leaf-extract, had 100% mortality 4 h after examination. Five worms used per treatment were submerged in ethanol and incubated for 24 hours. The ultrastructural changes observed by SEM revealed structural alteration of the worm surface after in vitro contact with the bamboo leaf aqueous extract and compared to the control worms. The main changes concerned the anterior end or cephalic region, cuticle surface, and vulva flap area. The structural modification of the external part of the female reproductive system was found only in vitro. The structural changes found in the worms exposed to the bamboo leaves might affect their motility and nutrition with possible consequences on their reproduction. Transmission electron microscopy may help to understand the external changes observed in H. contortus.

scholarly journals In vitro Antifungal Activity of Senna alata Linn. Crude Leaf Extract

2010 ◽  
Vol 5 (3) ◽  
pp. 275-284 ◽  
Author(s):  
W.F. Sule ◽  
I.O. Okonko ◽  
T.A. Joseph ◽  
M.O. Ojezele ◽  
J.C. Nwanze ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Leaf Extract ◽  
Crude Leaf Extract ◽  
Senna Alata ◽  
In Vitro Antifungal Activity

scholarly journals Antagonism of Plant Pathogens by Calotropis procera

2021 ◽  
Vol 13 (4) ◽  
pp. 120
Author(s):  
Karla Danielle Nogueira Cardoso ◽  
Maria Josiane Martins ◽  
Thaisa Aparecida Neres de Souza ◽  
Isabelle Carolyne Cardoso ◽  
Patrícia Nirlane da Costa Souza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Aqueous Extract ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Calotropis Procera ◽  
Mycelial Growth Rate ◽  
Vitro Effect ◽  
Fungal Colony

Phomopsis sojae and Sclerotinia sclerotiorum are responsible for stem and pod dryness and white mold in soybean. These pathologies directly affect the quality of seeds/grains and compromise the entire plant. The use of extracts from different plants has been the subject of research for the control of several phytopathogens. Calotropis procera is among botanical species that synthesize efficient compounds for biocontrol. In this context, the aim of this study was to evaluate the in vitro effect of C. procera aqueous extract on P. sojae and S. sclerotiorum. The experiment was carried out in completely randomized blocks in a 2 × 5 factorial scheme (two fungi and five extract concentrations 0%, 5%, 10%, 15% and 20%) with 4 replicates. C. procera aqueous extract concentrations were added to Petri dishes containing PDA. After 48 hours, the mycelial growth rate was evaluated. After seven days of incubation, the fungal colony area, sporulation, and germination of P. sojae and S. sclerotiorum were evaluated. There was significant interaction between fungi × extract concentrations (p < 0.05) for all variables analyzed. The mycelial growth rate of P. sojae was lower than that of S. sclerotiorum. The diameter of the P. sojae fungal colony was smaller than that of S. sclerotiorum when concentrations of 5%, 10% and 15% were used. As the extract concentration increased, fungi sporulation and germination reduced.

scholarly journals Phaleria macrocarpa (Scheff.) Boerl fruit aqueous extract enhances LDL receptor and PCSK9 expression in vivo and in vitro

2011 ◽  
Vol 137 (1) ◽  
pp. 817-827 ◽  
Author(s):  
Soo Ching Chong ◽  
Mohamad Aziz Dollah ◽  
Pei Pei Chong ◽  
Abdullah Maha
Keyword(s):  
Aqueous Extract ◽  
Ldl Receptor ◽  
Phaleria Macrocarpa

scholarly journals In vitro antifungal activity of endophytic bacteria isolated from date palm (Phoenix doctylifera L.) against fungal pathogens causing leaf spot of date palm

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
H. H. Al-Nadabi ◽  
N. S. Al-Buraiki ◽  
A. A. Al-Nabhani ◽  
S. N. Maharachchikumbura ◽  
R. Velazhahan ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Endophytic Bacteria ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Date Palm ◽  
Dual Culture ◽  
Bacterial Endophytes ◽  
Bacterial Strains ◽  
Culture Filtrates

Abstract Background Date palm ((Phoenix doctylifera L.) suffers from several fungal diseases. The endophytic microorganisms present in higher plants generally offer protection to their host plants against invading phytopathogenic fungi and bacteria. In the present study, endophytic bacteria associated with date palm leaves were isolated and their in vitro antagonistic potential against fungal pathogens causing leaf spots in date palm was demonstrated. Results Endophytic bacteria were isolated from date palm leaves of 3 different cultivars viz., Nighal, Khalas and Khinaizi and evaluated for their inhibitory activity against leaf spot pathogens of date palm viz., Fusarium solani, Alternaria sp., Nigrospora sp., Thieloviopsis sp., Curvularia subpapendrofii and Tilletiopsis minor using an in vitro dual culture assay. Of the 24 endophytic bacterial strains tested, the endophytes designated B1, B7, B8 and B9 obtained from cv. Nighal showed inhibitory activities (more than 55% mycelial growth inhibition) against F. solani and Alternaria sp. None of the bacterial endophytes inhibited the growth of other fungal pathogens tested. These antagonistic bacterial strains were identified as Pantoea septica on the basis of 16S rRNA gene sequence analysis. The hyphae of F. solani and Alternaria sp. exhibited morphological abnormalities such as shrinkage and disintegration when grown in the presence of antagonistic bacterial endophytes. The cell-free culture filtrates of the bacterial endophytes caused inhibition of mycelial growth and induced leakage of electrolytes from the mycelia of F. solani and Alternaria sp. This is the first study that describes inhibition of the date palm pathogens F. solani and Alternaria sp. by P. septica. Conclusion Endophytic Pantoea septica strains isolated from date palm leaves inhibited the mycelial growth of F. solani and Alternaria sp. and induced morphological changes in their mycelia. The culture filtrates of these bacterial strains also inhibited the mycelial growth and caused leakage of electrolytes from the mycelia of F. solani and Alternaria sp. These promising bacterial strains can be exploited as biocontrol agents to control F. solani and Alternaria sp.-induced leaf spot diseases of date palm.

scholarly journals In vitro evaluation of grapevine endophytes, epiphytes and sap micro-organisms for potential use to control grapevine trunk disease pathogens

2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen
Keyword(s):  
Biological Control ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Dual Culture ◽  
Biological Control Agents ◽  
In Planta ◽  
Eutypa Dieback ◽  
Fungal Isolates ◽  
Wound Protection

SummaryGrapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture worldwide causing a significant reduction of both yields and quality of grapes. Biological control presents a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from a variety of grapevine tissues, including sap, cane and pith and evaluate their antagonistic activity against selected fungal pathogens responsible for GTDs in vitro. Bacterial and fungal isolates were preliminary screened in vitro to determine their antifungal activity via a dual culture assay against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited E. lata mycelial growth up to 64% and N. parvum mycelial growth up to 73% with overgrowth and stopped growth being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited E. lata mycelial growth up to 20% and N. parvum mycelial growth up to 40%. Select antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subject to further dual culture antifungal analysis against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analysis revealed that these Trichoderma isolates resulted significantly inhibited mycelial growth of N. parvum, E. lata and D. ampelina causing up to 20.11%, 60.55% and 70.9% inhibition respectively (P≤0.05). Multilocus sequence analysis revealed that the Trichoderma isolates are most closely related to Trichoderma asperellum and Trichoderma hamatum. This study identifies grapevine sap as a novel source of potential biological control agents for control of GTDs to support existing efforts to control GTDs. Further testing will be necessary to fully characterize these microbes mode of antagonism and assess their efficacy for pruning wound protection in planta.

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