scholarly journals Severity of Phytophthora leaf blight disease and susceptibility of two local varieties of Colocasia to Phytophthora colocasiae Raciborski in Nsukka zone of South Eastern Nigeria

Bio-Research ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 1286-1296
Author(s):  
Faustina Njideka Ugwuja ◽  
Chiemeka Nwakaego Onaebi ◽  
Nneka Virginia Chiejina ◽  
Kelvin Ikechukwu Ugwuoke
Keyword(s):  
Disease Severity ◽  
Leaf Surface ◽  
Average Diameter ◽  
Colocasia Esculenta ◽  
Leaf Blight ◽  
Test Results ◽  
Local Varieties ◽  
Potted Plants ◽  
Phytophthora Colocasiae ◽  
Blight Disease

Leaf-blight disease of Colocasia caused by Phytophthora colocasiae Raciborski has been a serious impediment to cocoyam production in Nigeria. Disease severity and susceptibility of the two most cultivated local varieties “Ugwuta” (Colocasia esculenta var. antiquorum) and “Nkashi Colocasia esculenta var. esculenta) were investigated. Disease severity was visually estimated as the percentage leaf surface affected by blight, lesion or lesion-related chlorosis for each leaf of a plant using a seven-point scale of 0, 5, 10, 25, 50, 75 and 100% in three locations: Ede-Oballa, Nsukka Urban and Obukpa. Susceptibility was assessed on 2 months old potted plants of each variety inoculated with a 7-day old culture of P. colocasiae. Diameters of lesions on inoculated leaves were recorded from the 3rd - 8th day after inoculation.  Data on severity were subjected to ANOVA and susceptibility of the varieties was compared with t-test. Results revealed significant LSD=4.96 (0.05) and varying degrees of leaf blight severity among varieties and locations. Variety antiquorum had significantly higher severities of 42.08, 46.40 and 47.42% at Ede-Oballa, Nsukka Urban and Obukpa respectively, compared to 34.85, 36.55 and 28.19% recorded by var. esculenta at these locations, respectively. Similarly, var. antiquorum had greater lesion diameter ranging from 0.65±0.07 cm - 3.70±0.14 cm and average diameter of 2.4±0.16cm compared to var. esculenta which had 0.41±0.14cm - 3.12±0.19 cm and average diameter of 1.80±0.16. This research has shown that varieties and locations affect the severity and susceptibility of Phytophthora leaf blight disease. This could be a guide to farmers having known that var. esculenta is less severe to Phytophthora leaf blight disease.

scholarly journals Influence of weather parameters on alternaria leaf blight severity of makhana under the agro-climate of Koshi region of Bihar

2021 ◽  
Vol 23 (1) ◽  
pp. 54-59
Author(s):  
SANTOSH KUMAR ◽  
MD. NADEEM AKHTAR ◽  
SANTOSH KUMAR ◽  
MAHESH KUMAR ◽  
TRIBHUWAN KUMAR
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Disease Severity ◽  
Infection Process ◽  
Leaf Blight ◽  
Alternaria Leaf Blight ◽  
Weather Parameters ◽  
Maximum Temperatures ◽  
Blight Disease ◽  
Cent Disease

Weather parameters play a pivotal role in the infection process and spread of pathogen. It also influences the expression of susceptibility/resistance of the host plant during post-infection phases. Therefore, an experiment was conducted for two consecutive cropping seasons (2018 &2019) to study the influence of weather parameters such as temperature, humidity, rainfall and wind direction on the emergence of alternaria leaf blight of makhana in Koshi region of Bihar. Maximum per cent disease severity of alternarialeaf blightwas observed during the peak monsoon months (June to August). Highest disease severity of leaf blight (14.80% & 15.7%) was observed in the mid June during crop season, 2018 and 2019. High temperature (36.9oC & 38.1oC), and relative humidity (94% & 96.4%) of both the year 2018 and 2019 were found correlated with higher severity to alternaria leaf blight. Similarly average HTR values (3.1) were also found correlated with the average high temperature and relative humidity of both years (2018 and 2019) in terms of severity of leaf blight disease. Maximum temperatures, relative humidity and rainfall exhibited strong positive linear relationship and influenced the occurrence of alternaria leaf blight disease significantly. We also developed a geo-phytopathological model for the prediction of alternaria leaf blight disease of makhana on the basis of congenial mean temperature and relative humidity.

scholarly journals Assessing Taro (Colocasia esculenta (L.) Schott) Leaf Blight Incidence, Severity, and Farmers’ Knowledge of the Disease in Fako Division of Cameroon

2020 ◽  
pp. 17-29
Author(s):  
Mandah Cicelia Takor ◽  
Ekwa Yawa Monono ◽  
Ojong Agbor Ntane ◽  
Jemimah Evenye Ngale ◽  
Lum A. Fontem
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Management Strategies ◽  
Leaf Blight ◽  
Cultural Methods ◽  
Randomized Design ◽  
High Prevalence ◽  
Severity Of The Disease ◽  
Blight Disease ◽  
Taro Leaf Blight

Taro leaf blight (TLB), a major disease of taro plant caused by Phytophthora colocasiae, a pseudo-fungus, that occurs in many taro producing areas, especially in the South West of Cameroon. A Survey was conducted to assess farmers’ knowledge, as well as to determine the incidence and the severity of the disease in taro fields. Structured questionnaires were administered in selected locations (Bokova, Ekona, Muea, Mile 16, Mutengene, and Likomba) of taro production. Two farms were selected with two quadrats of 64 m2 each were carved to assess disease incidence and severity on taro. The number of plants infected with taro leaf blight were counted and the area of the affected leaves measured was used to evaluate the disease incidence and disease severity. Data collected were subjected to ANOVA for complete randomized design and the means were compared using Tukey test at 0.05 probability levels. The results revealed that most of the farmers could identify the disease while practicing cultural methods in controlling the disease. The results also revealed significant differences (p = 0.001) in disease incidence and disease severity in all the localities, with Mile 16 showing the highest percentage mean of 96.53% and 85.59%, respectively. The severity scored showed high infection range of 3 – 3.95 in all locations except in Likomba (2.60).  It could be concluded from the results that there were high prevalence of taro leaf blight disease in Fako Division. Good management strategies are therefore required to control Taro leaf blight and improve taro production in the area.

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

scholarly journals Field Performance of BAU-Biofungicaide for Management of Narrow Brown Leaf Spot and Bacterial Leaf Blight Disease of Rice CV. BRRI Dhan29

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Hyat Mahmud
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Seed Quality ◽  
Field Performance ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Leaf Spot Disease ◽  
Brown Leaf Spot ◽  
Brown Leaf ◽  
Blight Disease

Potent (0.1%) and BAU-Biofungicide (2%) revealed the significant reduction both in disease severity and incidence of narrow brown leaf spot disease, and the lowest disease severity and incidence of bacterial leaf blight disease were 3.00% and 5.83%, respectively in BRRI dhan29 in 2012 year. BAU-Biofungicide (Trichoderma based preparation), extract of garlic (Allium sativum) and neem (Azadirachta indica), Bavistin DF (Carbandazim) and Potent 250 EC (Propiconazole) were evaluated in controlling narrow brown leaf spot and bacterial leaf blight disease (Xanthomonas oryzae pv. Oryzae) under field condition for producing seed quality and controlling seed borne pathogen of rice cv BRRI dhan29 during 2012 and 2013 years. Maximum normal seedling (87.67%) and 37.49% higher increase in vigour index on seed quality test of harvested seeds were observed with BAU-Biofungicide (3%) over control. BAU-Biofungicide (2 and 3%) and Potent 250 EC (0.1%) were found to be effective in controlling seed borne pathogens. BAU-Biofungicide has also been attributed as profound contribution on quality seed production of harvested seed of BAU-Biofungicide sprayed plot.

Analysis of genetic diversity in Phytophthora colocasiae causing leaf blight of taro (Colocasia esculenta) using AFLP and RAPD markers

2013 ◽  
Vol 64 (1) ◽  
pp. 185-197 ◽  
Author(s):  
Vishnu Sukumari Nath ◽  
Muthukrishnan Senthil Alias Sankar ◽  
Vinayaka Mahabaleswar Hegde ◽  
Muthulekshmi Lajapathy Jeeva ◽  
Raj Shekar Misra ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Colocasia Esculenta ◽  
Leaf Blight ◽  
Phytophthora Colocasiae

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
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