scholarly journals Efficacy of spraying intervals of Ridomil Plus 66 WP for control of taro leaf blight disease

1970 ◽  
Vol 29 (1) ◽  
pp. 133-140
Author(s):  
J. Adomako ◽  
N.E. Amengor ◽  
S. Larbi-Koranteng ◽  
F. Kankam
Keyword(s):  
Yield Loss ◽  
Disease Incidence ◽  
Economic Benefits ◽  
Weekly Interval ◽  
Leaf Blight ◽  
Total Revenue ◽  
Optimum Period ◽  
Blight Disease ◽  
Taro Leaf Blight ◽  
Biweekly Interval

Taro leaf blight causes up to 100% yield loss in susceptible taro (Colocasia esculenta L. (Schott)) cultivars. The use of fungicides in disease management is fast and effective; however efficacy of fungicides could be affected by frequency of application. The objective of this study was to evaluate the efficacy of spraying intervals and economic benefits of Ridomil Plus 66 WP (12% Metalaxyl-M and 60% Copper (1) oxide) on taro leaf blight disease. The study consisted of four fungicide spraying intervals, viz at one, two and at four weekly intervals, all at the concentration of 3.3 g l-1 and no fungicide application as the control. Results showed no significant differences (P > 00.5) between one and two weekly spraying intervals in terms of taro leaf blight disease incidence and severity. These were, however, significantly different (P < 0.05) from four weekly and no fungicide applications. Taro corm yield was higher in weekly spraying interval, but not significantly different (P > 0.05) from biweekly application intervals. Yields in weekly intervals were 2.9, 33.0 and 44.0% higher than biweekly, four weekly and no application intervals. Applying fungicide at a biweekly interval was found to be economically efficient as it recorded higher total revenue and net present values. Applying 66 WP (12% Metalaxyl-M and 60% Copper (1) oxide) at 2 weekly interval was the optimum period and most efficient to reduce the incidence and severity of Phytophthora leaf blight disease and increase yield of taro.

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.

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

scholarly journals Incidence of leaf blight disease of Egusi melon in South-west Nigeria

2020 ◽  
Vol 28 (2) ◽  
pp. 255-265
Author(s):  
J.F. Ogunsola ◽  
B. Ikotun ◽  
K.E. Ogunsola
Keyword(s):  
Fungal Pathogens ◽  
Citrullus Lanatus ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Economic Damage ◽  
Colletotrichum Truncatum ◽  
Southwestern Nigeria ◽  
Lasiodiplodia Theobromae ◽  
Ondo State ◽  
Blight Disease

Egusi melon (Citrullus lanatus (Thumb) Mansf.) is an important vegetable crop grown for edible seeds and oil in West Africa. Leaf Blight Disease (LBD) is one of the major constraints to its production, with potential to cause economic damage. The objective of this study was to investigate the incidence and distribution of leaf blight on Egusi melon in Southwestern Nigeria. A survey of LBD of Egusi melon was conducted in 2015 and 2016, in five southwestern States of Nigeria (Ogun, Oyo, Osun, Ekiti and Ondo States). Twenty plants each, were randomly sampled from 150 farms comprising 30 farms each, from each State. The distribution of different Egusi melon varieties planted was recorded. “Bara” cv. was the most cultivated variety (51.6%); followed by “Bojuri” (30.4%) and “Serewe” (18%). Leaf blight was observed in most farms in the five States, from 73% in Osun and Oyo states to 83% in Ondo State. Disease incidence and severity varied with locations and cultivars, and ranged from 0.0-87.5±18% and 1.0±0-4.5±0.8 in Osun State to 20.0±19 - 95.0±4.5% and 2.3±1.5 - 5.0±0 in Ondo State. Out of the twelve fungal pathogens from ten genera isolated from infected plants, only Colletotrichum truncatum, C. gloeosporioides and Lasiodiplodia theobromae caused Leaf blight on Egusi melon. Key words: Colletotrichum gloeosporioides, Colletotrichum truncatum, Lasiodiplodia theobromae

scholarly journals Management of Leaf Blight Disease Caused by Alternaria polianthi in Tuberose

2020 ◽  
pp. 12-17
Author(s):  
M. R. Ravikumar ◽  
D. K. Harish ◽  
B. H. Kumara ◽  
Amarendra Kumar
Keyword(s):  
High Temperature ◽  
Yield Loss ◽  
Maximum Yield ◽  
Disease Index ◽  
Leaf Blight ◽  
Growth Reduction ◽  
Severe Problem ◽  
Tropical Areas ◽  
Percent Disease Index ◽  
Blight Disease

Tuberose is an ornamental crop which is growing under tropical and sub-tropical areas. Recently, the incidence of leaf blight disease caused by Alternaria polianthi a fungal disease of tuberose is considered as a severe problem causing growth reduction and yield loss triggered by high temperature and humidity. Hence an investigation was carried out in farmer fields at Tumnakatti, Ranebennurtq in Karnataka, to study the bio-efficacy of different fungicides against leaf blight of tuberose. There were six chemicals viz., Tebuconazole 250 EC @ 0.1%, Difenconazole – 25% EC @ 0.1%, Propinoconazole 25% EC @ 0.1%,  Hexaconazole  2% SC @ 0.1%, Mancozeb75 WP @ 0.25%, Chlorothalonil 75 WP @ 0.2%, were evaluated in tuberose cultivar Prajwal during kharif  2016 and 2017. Among the different fungicides, four sprays taken with Tebuconazole @ 0.1% at 15 days interval starting from onset of disease proved to be the most effective treatment and resulted in lowest percent disease index, PDI (10.80). Maximum yield and number of flower stalks per square meter area were recorded in Tebuconazole @ 0.1% (50.90). Tebuconazole @ 0.1% could be used for management of leaf blight and increase the yield of tuberose.

scholarly journals SKRINING DAN IDENTIFIKASI ISOLAT BAKTERI ENDOFIT UNTUK MENGENDALIKAN PENYAKIT HAWAR DAUN BAKTERI PADA BAWANG MERAH

2013 ◽  
Vol 13 (2) ◽  
pp. 167-178
Author(s):  
Zurai Resti ◽  
Trimurti Habazar ◽  
Deddi Prima Putra ◽  
Nasrun Nasrun
Keyword(s):  
Bacillus Cereus ◽  
Endophytic Bacteria ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Bacillus Sp ◽  
In Planta ◽  
16S Rrna Sequence ◽  
Randomized Design ◽  
Blight Disease

Screening and identification of endophytic bacteria to control bacterial leaf blight disease on Shallot. The experiment was conducted in Laboratory and Green House, from January to June 2012.   Laboratory experiment consisted of three steps:  (1) isolation of endophytic bacteria from healthy onion roots, (2)In planta /screening of endophytic isolates capable of reducing bacterial leaf blight disease, and (3) molecular identification of potential endophytic isolates.  Treatments of  in planta test were arranged in Completely Randomized Design.  Collected isolates were tested for their capability in controlling bacterial leaf blight disease on shallot.  The variables observed were disease incidence, disease severity, and shallot yield. The results showed that out of 82 isolates successfully isolated, 56 isolates (68.29%) were Gram positive, and 26 isolate (31.71%) were Gram negative. All isolates were HR negative and pathogenicity negative. Six endophytic isolates showed  better performance in inducing resistance and increasing onion yield. Based on 16S rRNA sequence the six isolates were  Bacillus cereus strain P14 , Bacillus cereus strain Se07, Bacillus sp H1, Bacillus sp SJ1 and Serratia marcescens strain PPM4.

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.

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