scholarly journals Comparison of severity of Phytophthora colocasiae (taro leaf blight) disease on in-vivo and in-vitro Pacific-Caribbean and Kenyan taro (Colocasiae esculenta) grown in Kakamega county (Kenya)

2019 ◽  
Vol 6 (2) ◽  
pp. 040-051
Author(s):  
Carren Adhiambo Otieno ◽  
Valerie Palapala Adema ◽  
George Timothy Opande
Keyword(s):  
Leaf Blight ◽  
Phytophthora Colocasiae ◽  
Blight Disease ◽  
Taro Leaf Blight

A Rapid and Efficient Method for In Vitro Screening of Taro for Leaf Blight Disease Caused by Phytophthora colocasiae

2016 ◽  
Vol 164 (7-8) ◽  
pp. 520-527
Author(s):  
Vishnu Sukumari Nath ◽  
Shyni Basheer ◽  
Muthulekshmi Lajapathy Jeeva ◽  
Vinayaka Mahabaleswar Hegde ◽  
Asha Devi ◽  
...  
Keyword(s):  
Efficient Method ◽  
Leaf Blight ◽  
In Vitro Screening ◽  
Phytophthora Colocasiae ◽  
Blight Disease

Morphological, pathological and molecular characterization of Phytophthora colocasiae responsible for taro leaf blight disease in India

2014 ◽  
Vol 43 (1) ◽  
pp. 21-35 ◽  
Author(s):  
Vishnu Sukumari Nath ◽  
Vinayaka Mahabaleswar Hegde ◽  
Muthulekshmi Lajapathy Jeeva ◽  
Raj Shekar Misra ◽  
Syamala Swayamvaran Veena ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Leaf Blight ◽  
Phytophthora Colocasiae ◽  
Blight Disease ◽  
Taro Leaf Blight

scholarly journals Detached-Leaf Bioassay for Evaluating Taro Resistance to Phytophthora colocasiae

Plant Disease ◽  
2008 ◽  
Vol 92 (1) ◽  
pp. 126-131 ◽  
Author(s):  
F. E. Brooks
Keyword(s):  
Pacific Islands ◽  
Cropping Systems ◽  
American Samoa ◽  
Leaf Blight ◽  
Limiting Factor ◽  
Detached Leaf ◽  
Phytophthora Colocasiae ◽  
Highly Correlated ◽  
Blight Disease ◽  
Taro Leaf Blight

Taro leaf blight disease, caused by Phytophthora colocasiae, is a major limiting factor in taro production worldwide. P. colocasiae is an aerial pathogen similar to P. infestans, causal agent of potato late blight disease, but occurs in warmer climates. In the year-round subsistence cropping systems of the Pacific Islands, resistant cultivars are essential. Breeding lines from Southeast Asia and Oceania were tested in American Samoa for resistance to taro leaf blight using a detached-leaf bioassay and field trials. Mean lesion diameters from bioassays were highly correlated with field estimates of the number of healthy leaves per plant and yield (corm weight). However, the bioassay did not adequately assess infection efficiency. Additional experiments revealed that attached leaves had smaller lesion diameters than detached leaves incubated in closed containers, but both were very highly correlated. Taro resistance increased with plant age and the second-oldest leaf was more resistant than the third-oldest leaf. The bioassay was a fast, space-saving, effective method of screening taro lines for post-penetration resistance to P. colocasiae. It also provided an easily standardized method of evaluating host–pathogen interactions under controlled conditions.

scholarly journals In Vitro and In Vivo Antifungal Activity of Sorbicillinoids Produced by Trichoderma longibrachiatum

2021 ◽  
Vol 7 (6) ◽  
pp. 428
Author(s):  
Men Thi Ngo ◽  
Minh Van Nguyen ◽  
Jae Woo Han ◽  
Myung Soo Park ◽  
Hun Kim ◽  
...  
Keyword(s):  
Late Blight ◽  
Culture Filtrate ◽  
Fungal Pathogens ◽  
Gray Mold ◽  
Trichoderma Longibrachiatum ◽  
Chemical Structures ◽  
Natural Agents ◽  
Blight Disease

In the search for antifungal agents from marine resources, we recently found that the culture filtrate of Trichoderma longibrachiatum SFC100166 effectively suppressed the development of tomato gray mold, rice blast, and tomato late blight. The culture filtrate was then successively extracted with ethyl acetate and n-butanol to identify the fungicidal metabolites. Consequently, a new compound, spirosorbicillinol D (1), and a new natural compound, 2′,3′-dihydro-epoxysorbicillinol (2), together with 11 known compounds (3–13), were obtained from the solvent extracts. The chemical structures were determined by spectroscopic analyses and comparison with literature values. The results of the in vitro antifungal assay showed that of the tested fungal pathogens, Phytophthora infestans was the fungus most sensitive to the isolated compounds, with MIC values ranging from 6.3 to 400 µg/mL, except for trichotetronine (9) and trichodimerol (10). When tomato plants were treated with the representative compounds (4, 6, 7, and 11), bisvertinolone (6) strongly reduced the development of tomato late blight disease compared to the untreated control. Taken together, our results revealed that the culture filtrate of T. longibrachiatum SFC100166 and its metabolites could be useful sources for the development of new natural agents to control late blight caused by P. infestans.

Thymol and its Derivatives for Management of Phytopathogenic fungi of maize

2021 ◽  
Vol 18 ◽  
Author(s):  
Jyoti Gaba ◽  
Sunita Sharma ◽  
Harleen Kaur ◽  
Pardeep Kaur
Keyword(s):  
Pathogenic Fungi ◽  
Bioactive Compound ◽  
Mannich Bases ◽  
Phytopathogenic Fungi ◽  
Leaf Blight ◽  
Significant Control ◽  
Thymol Derivatives ◽  
Potential Alternative ◽  
Blight Disease

Background: Thymol is a bioactive compound having many pharmacological activities. Objective: The present study was carried out to evaluate the fungi toxic effects of thymol and derivatives against phytopathogenic fungi of maize. Method: Thymol was derivatized to get formylated thymol, Mannich bases, and imine derivatives. All the synthesized thymol derivatives were characterized by their physical and spectral properties. Synthesized thymol derivatives were screened for their in vitro antifungal effects using poisoned food technique against three maize pathogenic fungi namely Fusarium moniliforme, Rhizoctonia solani and Dreschlera maydis. Results: Thymol and formylated thymol showed promising results for control of D. maydis with ED50 values less than standard carbendazim and comparable to standard mancozeb. These two compounds were further evaluated for control of D. maydis causative maydis leaf blight disease on maize plants grown in the field during the Kharif season (June to October) 2018. Conclusion: Thymol exhibited significant control of maydis leaf blight disease of maize and emerged as a potential alternative to synthetic fungicides used in cereal crops.

scholarly journals Management of Alternaria leaf blight in tomato plants by mentha essential oil

2020 ◽  
Vol 56 (No. 3) ◽  
pp. 191-196
Author(s):  
Kahkashan Perveen ◽  
Najat A. Bokhari
Keyword(s):  
Antifungal Activity ◽  
Essential Oil ◽  
Mycelial Growth ◽  
Leaf Blight ◽  
In Vitro Test ◽  
Tomato Plants ◽  
Conidia Germination ◽  
Alternaria Leaf Blight

The essential oil obtained by the hydro-distillation of the leaves of Mentha arvensis Linnaeus was evaluated for its antifungal activity against the causal agent of the Alternaria blight of tomatoes, i.e., Alternaria alternata (Fries) Keissler. The antifungal activity of the mentha essential oil was assessed both in vitro and in vivo. The chemical composition of the mentha oil was also identified by GCMS analysis. The in vitro test revealed that the maximum inhibition in the mycelial growth (93.6%) and conidia germination (90.6%) was at the highest concentration (40 µL/mL), furthermore, it was found that the inhibition of the mycelial growth and conidia germination was dose dependent. The in vivo test proved that the application of the mentha essential oil (40 µL/mL) significantly increased the plant height (84.6%), fresh weight (81.5%) and dry weight (80.0%) when compared to the untreated tomato plants. The disease incidence was 3.5 in the untreated plants, while it was 0.93 for the mentha essential oil treated plants and was 0.08 in the carbendazim treated plants. The GC-MS analysis of the mentha essential oil identified 18 compounds in total, among which the percentage of menthol was the highest (69.2%). The mentha essential oil was successful in managing the Alternaria leaf blight in the tomato plants. Therefore, it can be explored further for the development of a natural fungicide.

scholarly journals Prevalence and Severity of Leaf Blight Disease of Chrysanthemum in Southern regions of Karnataka and in-vitro Fungicidal Effect on Alternaria alternata

2015 ◽  
Vol 9 (3) ◽  
pp. 38-45 ◽  
Author(s):  
G. Shamala ◽  
G. R. Janardhana
Keyword(s):  
Alternaria Alternata ◽  
Disease Incidence ◽  
Life Sciences ◽  
Leaf Blight ◽  
Cut Flowers ◽  
In Vitro Evaluation ◽  
Karnataka State ◽  
Commercially Important ◽  
Blight Disease

Chrysanthemum is one of the commercially important flower crop with great potential both as loose and cut flowers in Karnataka state. In the present study, prevalence and incidence of leaf blight disease was studied in six major growing districts of South Karnataka during 2012 - 2013. The pathogen associated with leaf blight disease was isolated and identified as Alternaria alternata. The study revealed that, the disease was distributed in Southern districts of Karnataka wherever Chrysanthemum is grown. The varieties Chandini and Karnel were more susceptible to blight showing highest disease incidence (100%) and severity (100%) recorded from Mandya and Mysore regions. The lowest disease incidence, severity and PDI of 18.40%, 38.68% and 24.89% were recorded on Rajawhite variety in Bangalore region. During 2013, the highest disease incidence, severity and PDI with 100%, 98.47%, and 45.71% were recorded in Mysore district on Chandini variety. In vitro evaluation of four fungicides on Alternaria alternata revealed that Carbendazim+Mancozeb was most effective with 95.65% inhibition followed by Carbendazim, Mancozeb and Metalaxyl+Mancozeb with 68.26%, 91.30% and 91.30% inhibition of the mycelium at 2.0% concentration.DOI: http://dx.doi.org/10.3126/ijls.v9i3.12465   International Journal of Life Sciences 9 (3): 2015; 38-45

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